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Sample records for alamos magnetospheric plasma

  1. Magnetospheric Plasma Data from the Los Alamos Magnetospheric Plasma Analyzer (MPA)

    DOE Data Explorer

    NIS-1 MPA Team, LANL

    The MPA instruments were designed and built to measure the three-dimensional plasma, electron, and ion distributions at geosynchronous orbit [Bame et al.,Rev. Sci. Instrum., 1993]. MPAs have been fielded by Los Alamos National Laboratory, in collaboration with Sandia National Laboratory, on a series of geosynchronous spacecraft. The plasma environments sampled include the plasmasphere, the plasmasheet, the trough, the magnetosheath, the low latitude boundary layer, and the lobe. The resulting data plots analyze the occurrence frequency of MPA observations of these different plasma regimes as a function of local time. LANL's MPA website also provides access to two special event studies: The National Space Weather Initiative, conducted in November of 1993 and the ISTP Sun-Earth Connection Event, conducted in January of 1997.

  2. Origins of magnetospheric plasma

    SciTech Connect

    Moore, T.E. )

    1991-01-01

    A review is given of recent (1987-1990) progress in understanding of the origins of plasmas in the earth's magnetosphere. In counterpoint to the early supposition that geomagnetic phenomena are produced by energetic plasmas of solar origin, 1987 saw the publication of a provocative argument that accelerated ionospheric plasma could supply all magnetospheric auroral and ring current particles. Significant new developments of existing data sets, as well as the establishment of entirely new data sets, have improved the ability to identify plasma source regions and to track plasma through the magnetospheric system of boundary layers and reservoirs. These developments suggest that the boundary between ionospheric and solar plasmas, once taken to lie at the plasmapause, actually lies much nearer to the magnetopause. Defining this boundary as the surface where solar wind and ionosphere contribute equally to the plasma, it is referred to herein as the 'geopause'. It is now well established that the infusion of ionospheric O(+) plays a major role in the storm-time distention of the magnetotail and inflation of the inner magnetosphere. After more than two decades of observation and debate, the question remains whether magnetosheric are protons of solar or terrestrial origin. 161 refs.

  3. Plasmas in Saturn's magnetosphere

    NASA Technical Reports Server (NTRS)

    Frank, L. A.; Burek, B. G.; Ackerson, K. L.; Wolfe, J. H.; Mihalov, J. D.

    1980-01-01

    The solar wind plasma analyzer on board Pioneer 2 provides first observations of low-energy positive ions in the magnetosphere of Saturn. Measurable intensities of ions within the energy-per-unit charge (E/Q) range 100 eV to 8 keV are present over the planetocentric radial distance range about 4 to 16 R sub S in the dayside magnetosphere. The plasmas are found to be rigidly corotating with the planet out to distances of at least 10 R sub S. At radial distances beyond 10 R sub S, the bulk flows appear to be in the corotation direction but with lesser speeds than those expected from rigid corotation. At radial distances beyond the orbit of Rhea at 8.8 R sub S, the dominant ions are most likely protons and the corresponding typical densities and temperatures are 0.5/cu cm and 1,000,000 K, respectively, with substantial fluctuations. It is concluded that the most likely source of these plasmas in the photodissociation of water frost on the surface of the ring material with subsequent ionization of the products and radially outward diffusion. The presence of this plasma torus is expected to have a large influence on the dynamics of Saturn's magnetosphere since the pressure ratio beta of these plasmas approaches unity at radial distances as close to the planet as 6.5 R sub S. On the basis of these observational evidences it is anticipated that quasi-periodic outward flows of plasma, accompanied with a reconfiguration of the magnetosphere beyond about 6.5 R sub S, will occur in the local night sector in order to relieve the plasma pressure from accretion of plasma from the rings.

  4. Plasma in Saturn's magnetosphere

    NASA Technical Reports Server (NTRS)

    Eviatar, A.

    1984-01-01

    The spatial and compositional distribution of the thermal plasma in the magnetosphere of Saturn is described in the light of the Voyager encounters. Theoretical considerations are applied to the elucidation of the structure, including two external and two internal boundaries. The outer boundary is a magnetohydrodynamic entity, while the inner boundary of locally created thermal plasma is a result of the dissociative recombination of corotating molecular ions. The internal boundaries, which separate plasmas of different composition, are explained as a charge exchange quasi-resonance phenomenon.

  5. Plasma convection in Neptune's magnetosphere

    NASA Technical Reports Server (NTRS)

    Selesnick, R. S.

    1990-01-01

    The magnetosphere of Neptune changes its magnetic configuration continuously as the planet rotates, leading to a strong modulation of the convection electric field. Even though the corotation speed is considerably larger, the modulation causes the small convection speed to have a cumulative effect, much like the acceleration of particles in a cyclotron. A model calculation shows that plasma on one side of the planet convects out of the magnetosphere in a few planetary rotations, while on the other side it convects slowly planetward. The observation of nitrogen ions from a Triton plasma torus may provide a critical test of the model.

  6. Plasma in the Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1975-01-01

    It is shown that the plasma in Jupiter's ionosphere is collisionless above a certain level. In the outer magnetosphere, where the rotational force dominates the gravitational force, the collisionless plasma has a beam-like distribution and gives rise to a two-stream instability. This leads to trapping of plasma in the centrifugally dominated region of the magnetosphere. Plasma is lost by recombination. Equilibrium-trapped particle densities are calculated by requiring a balance between trapping by wave-particle interaction and loss by recombination. The results are compared with recent observations from Pioneer 10. It is suggested that the observations require an unexplained ion-heating mechanism. Some consequences of the model are discussed.

  7. Plasma Circulation in the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Fok, Mei-Ching; Delcourt, D. C.; Slinker, S.; Fedder, J. A.; Buenfil, M.

    2006-01-01

    We investigate the global structure and dynamics of plasma circulation produced by prototypical solar wind disturbances of the interplanetary magnetic field and dynamic pressure. We track the global circulation and energization of solar wind, polar wind, and auroral wind plasmas throughout the magnetosphere, until they precipitate or escape into the downstream solar wind. We use the full equations of motion of the plasma ions within fields produced by a global MHD simulation of the dynamic solar wind interaction. We use the dynamic hot plasma density and Poynting energy flux specified at the inner boundary of the MHD simulation as drivers of conjugate ion outflow fluxes using local empirical relations obtained from the FAST and Polar missions. Birkeland currents computed by the MHD code are used to derive a field-parallel potential drop from a Knight-like relation [as modified by Lyons and Evans, 1980]. This potential drop is applied to each ion as an initial bulk energy, added to a thermal heating driven by the locally incident Poynting flux. The solar wind pressure increase case (B(sub Y) = 5; B(sub z) = 0 nT) produces an immediate substorm owing to compression of pre-existing plasmas. The SB(sub z), interval (embedded in NB(sub z)) produces a substorm after about one hour of development. Both disturbances enhance the auroral wind flux and heavy ion pressure of the magnetosphere substantially, with complex dynamic structuring by auroral acceleration vortexes and dynamic reconnection. Comparisons are made with observations during disturbed periods including the Halloween 2003 super-storm and other periods.

  8. Plasma Sources and Magnetospheric Consequences at Saturn

    NASA Astrophysics Data System (ADS)

    Thomsen, M. F.

    2012-12-01

    Saturn's magnetospheric dynamics are dominated by two facts: 1) the planet rotates very rapidly (~10-hour period); and 2) the moon Enceladus, only 500 km in diameter, orbits Saturn at a distance of 4 Rs. This tiny moon produces jets of water through cracks in its icy surface, filling a large water-product torus of neutral gas that surrounds Saturn near Enceladus' orbit. Through photoionization and electron-impact ionization, the torus forms the dominant source of Saturn's magnetospheric plasma. This inside-out loading of plasma, combined with the rapid rotation of the magnetic field, leads to outward transport through a nearly continuous process of discrete flux-tube interchange. The magnetic flux that returns to the inner magnetosphere during interchange events brings with it hotter, more-tenuous plasma from the outer magnetosphere. When dense, relatively cold plasma from the inner magnetosphere flows outward in the tail region, the magnetic field is often not strong enough to confine it, and magnetic reconnection allows the plasma to break off in plasmoids that escape the magnetospheric system. This complicated ballet of production, transport, and loss is carried on continuously. In this talk we will investigate its temporal variability, on both short and long timescales.

  9. Dusty Plasmas in Planetary Magnetospheres Award

    NASA Technical Reports Server (NTRS)

    Horanyi, Mihaly

    2005-01-01

    This is my final report for the grant Dusty Plasmas in Planetary Magnetospheres. The funding from this grant supported our research on dusty plasmas to study: a) dust plasma interactions in general plasma environments, and b) dusty plasma processes in planetary magnetospheres (Earth, Jupiter and Saturn). We have developed a general purpose transport code in order to follow the spatial and temporal evolution of dust density distributions in magnetized plasma environments. The code allows the central body to be represented by a multipole expansion of its gravitational and magnetic fields. The density and the temperature of the possibly many-component plasma environment can be pre-defined as a function of coordinates and, if necessary, the time as well. The code simultaneously integrates the equations of motion with the equations describing the charging processes. The charging currents are dependent not only on the instantaneous plasma parameters but on the velocity, as well as on the previous charging history of the dust grains.

  10. Detached plasma in Saturn's front side magnetosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1983-01-01

    Plasma observations in the outer front side Saturnian magnetosphere are discussed which indicate the existence of dense flux tubes outside the plasma sheets. It is suggested that flux tubes are detached from the plasma sheet by a centifugally driven flute instability. The same instability leads to a dispersal of Titan-injected plasma. It is shown that the detached flux tubes will probably break open as they convect into the nightside magnetotail and lose their content in the form of a planetary wind.

  11. LANL Studies Earth's Magnetosphere

    ScienceCinema

    Daughton, Bill

    2016-07-12

    A new 3-D supercomputer model presents a new theory of how magnetic reconnection works in high-temperature plasmas. This Los Alamos National Laboratory research supports an upcoming NASA mission to study Earth's magnetosphere in greater detail than ever.

  12. LANL Studies Earth's Magnetosphere

    SciTech Connect

    Daughton, Bill

    2011-04-15

    A new 3-D supercomputer model presents a new theory of how magnetic reconnection works in high-temperature plasmas. This Los Alamos National Laboratory research supports an upcoming NASA mission to study Earth's magnetosphere in greater detail than ever.

  13. Large-Scale Structure of Magnetospheric Plasma

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Delcourt, D. C.

    1995-01-01

    Recent investigations of magnetospheric plasma structure are summarized under the broad categories of empirical models, transport across boundaries, formation, and dynamics of the plasma sheet. This report reviews work in these areas during the period 1991 to 1993. Fully three-dimensional empirical models and simulations have become important contributors to our understanding of the magnetospheric system. Some new structural concepts have appeared in the literature: the 'entry boundary' and 'geo-pause', the plasma sheet 'region 1 vortices', the 'low-energy layer', the 'adia-baticity boundary' or 'wall region', and a region in the tail to which we refer as the 'injection port'. Traditional structural concepts have also been the subject of recent study, notably the plasmapause, the magnetopause, and the plasma sheet. Significant progress has been made in understanding the nature of plasma sheet formation and dynamics, but the acceleration of electrons to high energy remains somewhat mysterious.

  14. Radial plasma transport in Saturn's magnetosphere (Invited)

    NASA Astrophysics Data System (ADS)

    Hill, T. W.

    2010-12-01

    Radial plasma transport in the magnetosphere of Saturn, like that of Jupiter, is driven by the centrifugal force of (partial) corotation acting on internally generated plasma. A significant difference is that the internal plasma source is evidently broadly distributed throughout the inner magnetosphere of Saturn (4 < L <~12), although the neutral water vapor source is evidently tightly localized to Enceladus (L = 4). At Jupiter, by comparison, both the neutral and plasma sources are evidently largely confined to the Io plasma torus (L ~ 6-7). A possible consequence of the broadly distributed source at Saturn is the observed feature that convective outflow channels are relatively broad and slow, while the corresponding inflow channels are relatively narrow and fast. This feature is well documented by Cassini observations (primarily CAPS and MAG), and reproduced in numerical simulations (RCM) that contain a distributed plasma source, although it has not, to my knowledge, been explained by an analytical theory containing an active plasma source. Both planets exhibit strong magnetospheric modulations near the planetary spin period, probably indicating a persistent longitudinal asymmetry of the radial plasma transport process. At Jupiter such an asymmetry is readily understood as a consequence of the dramatic asymmetry of the intrinsic planetary magnetic field. This is not so at Saturn, where any such field asymmetry is known to be very modest at best. In neither case has the precise nature of the asymmetry been identified either observationally or theoretically.

  15. Predicting the magnetospheric plasma of weather

    NASA Technical Reports Server (NTRS)

    Dawson, John M.

    1986-01-01

    The prediction of the plasma environment in time, the plasma weather, is discussed. It is important to be able to predict when large magnetic storms will produce auroras, which will affect the space station operating in low orbit, and what precautions to take both for personnel and sensitive control (computer) equipment onboard. It is also important to start to establish a set of plasma weather records and a record of the ability to predict this weather. A successful forecasting system requires a set of satellite weather stations to provide data from which predictions can be made and a set of plasma weather codes capable of accurately forecasting the status of the Earth's magnetosphere. A numerical magnetohydrodynamic fluid model which is used to model the flow in the magnetosphere, the currents flowing into and out of the auroral regions, the magnetopause, the bow shock location and the magnetotail of the Earth is discussed.

  16. Magnetospheric control of the bulk ionospheric plasma

    SciTech Connect

    Sojka, J.J.; Schunk, R.W.

    1987-01-01

    The temperature, composition, and circulation of the high-latitude, ionosphere display a marked variation with altitude, latitude, longitude, universal time, season, solar cycle, and geomagnetic activity. This variation is largely a consequence of the effect that magnetospheric electric fields, particle precipitation, and heat flows have on the ionosphere. At F-region altitudes, the entire ionosphere drifts in response to magnetospheric electric fields, with the horizontal drift generally displaying a two-cell pattern of antisunward flow over the polar cap and return flow at lower latitudes. This ionospheric motion, in combination with downward magnetospheric heat flows and ion production due to energetic-particle precipitation, act to produce interesting ionospheric features such as ion and electron temperature hot spots, plasma blobs, localized ionization troughs, and extended tongue of ionization, and anomalous F-region peak altitudes and densities. The time delay for the ionosphere to respond to changing magnetospheric conditions is a strong function of altitude and can be as long as 3 to 4 hours in the upper F-region. The ionosphere's response to changing magnetospheric conditions are described using a time-dependent high-latitude ionospheric model.

  17. Magnetospheric radio and plasma wave research - 1987-1990

    SciTech Connect

    Kurth, W.S. )

    1991-01-01

    This review covers research performed in the area of magnetospheric plasma waves and wave-particle interactions as well as magnetospheric radio emissions. The report focuses on the near-completion of the discovery phase of radio and plasma wave phenomena in the planetary magnetospheres with the successful completion of the Voyager 2 encounters of Neptune and Uranus. Consideration is given to the advances made in detailed studies and theoretical investigations of radio and plasma wave phenomena in the terrestrial magnetosphere or in magnetospheric plasmas in general.

  18. Plasma and ion beam processing at Los Alamos

    SciTech Connect

    Rej, D.J.; Davis, H.A.; Henins, I.

    1994-07-01

    Efforts are underway at Los Alamos National Laboratory to utilize plasma and intense ion beam science and technology of the processing of advanced materials. A major theme involves surface modification of materials, e.g., etching, deposition, alloying, and implantation. In this paper, we concentrate on two programs, plasma source ion implantation and high-intensity pulsed ion beam deposition.

  19. Magnetospheric electrostatic emissions and cold plasma densities

    NASA Technical Reports Server (NTRS)

    Hubbard, R. F.; Birmingham, T. J.

    1978-01-01

    A synoptic study of electric wave, magnetometer, and plasma data from IMP-6 was carried out for times when banded electrostatic waves are observed between harmonics of the electron gyrofrequency in the earth's outer magnetosphere. Four separate classes of such waves were previously identified. The spatial and temporal occurrences of waves in each class are summarized here, as are correlations of occurrence with geomagnetic activity. Most importantly, associations between the observations of waves of different classes and the relative portions of cold and hot electrons present at the position of the spacecraft are established. Finally, evidence for the signature of the loss cone is sought in the plasma data.

  20. On plasma convection in Saturn's magnetosphere

    NASA Astrophysics Data System (ADS)

    Livi, Roberto

    We use CAPS plasma data to derive particle characteristics within Saturn's inner magnetosphere. Our approach is to first develop a forward-modeling program to derive 1-dimensional (1D) isotropic plasma characteristics in Saturn's inner, equatorial magnetosphere using a novel correction for the spacecraft potential and penetrating background radiation. The advantage of this fitting routine is the simultaneous modeling of plasma data and systematic errors when operating on large data sets, which greatly reduces the computation time and accurately quantifies instrument noise. The data set consists of particle measurements from the Electron Spectrometer (ELS) and the Ion Mass Spectrometer (IMS), which are part of the Cassini Plasma Spectrometer (CAPS) instrument suite onboard the Cassini spacecraft. The data is limited to peak ion flux measurements within +/-10° magnetic latitude and 3-15 geocentric equatorial radial distance (RS). Systematic errors such as spacecraft charging and penetrating background radiation are parametrized individually in the modeling and are automatically addressed during the fitting procedure. The resulting values are in turn used as cross-calibration between IMS and ELS, where we show a significant improvement in magnetospheric electron densities and minor changes in the ion characteristics due to the error adjustments. Preliminary results show ion and electron densities in close agreement, consistent with charge neutrality throughout Saturn's inner magnetosphere and confirming the spacecraft potential to be a common influence on IMS and ELS. Comparison of derived plasma parameters with results from previous studies using CAPS data and the Radio And Plasma Wave Science (RPWS) investigation yields good agreement. Using the derived plasma characteristics we focus on the radial transport of hot electrons. We present evidence of loss-free adiabatic transport of equatorially mirroring electrons (100 eV - 10 keV) in Saturn's magnetosphere between

  1. Magnetospheric plasma - Sources, wave-particle interactions and acceleration mechanisms.

    NASA Technical Reports Server (NTRS)

    Speiser, T. W.

    1971-01-01

    Some of the basic problems associated with magnetospheric physics are reviewed. The sources of magnetospheric plasma, with auroral particles included as a subset, are discussed. The possible ways in which the solar wind plasma can gain access to the magnetosphere are outlined. Some important consequences of wave-particle interactions are examined. Finally, the basic mechanisms which energize or accelerate particles by reconnection and convection are explained.

  2. Current status of IMS plasma wave research. [International Magnetospheric Study

    NASA Technical Reports Server (NTRS)

    Anderson, R. R.

    1982-01-01

    The present investigation is concerned with a review of the status of magnetospheric plasma wave science as a result of the International Magnetospheric Study (IMS). The presence of an international effort has supported the development and completion of the numerous magnetospheric science spacecraft launched during the IMS, including GEOS, ISEE, and EXOS B. Ground-based VLF observations are considered along with coordinated ground-based and satellite observations. During the IMS, plasma wave research using satellite data has covered a wide range of subjects. Attention is given to magnetospheric electrostatic emissions, magnetospheric electromagnetic plasma waves, continuum radiation, auroral kilometric radiation, auroral zone plasma waves, plasma waves in the magnetosheath and near the mangetopause, and plasma waves at the bow shock.

  3. Fast Plasma Investigation for Magnetospheric Multiscale

    NASA Astrophysics Data System (ADS)

    Pollock, C.; Moore, T.; Jacques, A.; Burch, J.; Gliese, U.; Saito, Y.; Omoto, T.; Avanov, L.; Barrie, A.; Coffey, V.; Dorelli, J.; Gershman, D.; Giles, B.; Rosnack, T.; Salo, C.; Yokota, S.; Adrian, M.; Aoustin, C.; Auletti, C.; Aung, S.; Bigio, V.; Cao, N.; Chandler, M.; Chornay, D.; Christian, K.; Clark, G.; Collinson, G.; Corris, T.; De Los Santos, A.; Devlin, R.; Diaz, T.; Dickerson, T.; Dickson, C.; Diekmann, A.; Diggs, F.; Duncan, C.; Figueroa-Vinas, A.; Firman, C.; Freeman, M.; Galassi, N.; Garcia, K.; Goodhart, G.; Guererro, D.; Hageman, J.; Hanley, J.; Hemminger, E.; Holland, M.; Hutchins, M.; James, T.; Jones, W.; Kreisler, S.; Kujawski, J.; Lavu, V.; Lobell, J.; LeCompte, E.; Lukemire, A.; MacDonald, E.; Mariano, A.; Mukai, T.; Narayanan, K.; Nguyan, Q.; Onizuka, M.; Paterson, W.; Persyn, S.; Piepgrass, B.; Cheney, F.; Rager, A.; Raghuram, T.; Ramil, A.; Reichenthal, L.; Rodriguez, H.; Rouzaud, J.; Rucker, A.; Saito, Y.; Samara, M.; Sauvaud, J.-A.; Schuster, D.; Shappirio, M.; Shelton, K.; Sher, D.; Smith, D.; Smith, K.; Smith, S.; Steinfeld, D.; Szymkiewicz, R.; Tanimoto, K.; Taylor, J.; Tucker, C.; Tull, K.; Uhl, A.; Vloet, J.; Walpole, P.; Weidner, S.; White, D.; Winkert, G.; Yeh, P.-S.; Zeuch, M.

    2016-03-01

    The Fast Plasma Investigation (FPI) was developed for flight on the Magnetospheric Multiscale (MMS) mission to measure the differential directional flux of magnetospheric electrons and ions with unprecedented time resolution to resolve kinetic-scale plasma dynamics. This increased resolution has been accomplished by placing four dual 180-degree top hat spectrometers for electrons and four dual 180-degree top hat spectrometers for ions around the periphery of each of four MMS spacecraft. Using electrostatic field-of-view deflection, the eight spectrometers for each species together provide 4pi-sr field-of-view with, at worst, 11.25-degree sample spacing. Energy/charge sampling is provided by swept electrostatic energy/charge selection over the range from 10 eV/q to 30000 eV/q. The eight dual spectrometers on each spacecraft are controlled and interrogated by a single block redundant Instrument Data Processing Unit, which in turn interfaces to the observatory's Instrument Suite Central Instrument Data Processor. This paper describes the design of FPI, its ground and in-flight calibration, its operational concept, and its data products.

  4. Some studies of whistler mode propagation in the magnetospheric plasma

    NASA Astrophysics Data System (ADS)

    Sazhin, S. S.

    1981-02-01

    Limits in the application of a cold plasma model to whistler propagation in the magnetospheric plasma are studied. It is pointed out that finite anisotropy of magnetospheric plasma can compensate for the influence of finite temperature on whistler propagation so that the cold plasma model can be applied. An approximate formula is obtained for whistler refractive index for the case of oblique propagation in a hot anisotropic plasma with a loss cone. This formula is applied to the problem of whistler energy focusing along the magnetic field in the homogeneous plasma and whistler mode propagation in magnetospheric ducts. The possibility of whistler trapping in ducts formed by temperature gradients in the magnetospheric plasma is pointed out.

  5. Alternative formulations of magnetospheric plasma electrodynamics

    NASA Technical Reports Server (NTRS)

    Cragin, B. L.; Heikkila, W. J.

    1981-01-01

    The fundamental equations of magnetospheric plasma electrodynamics are considered from a theoretical standpoint that stresses the basic equivalence of various seemingly different formal representations. The mathematical properties of vector fields are reviewed, and their implications in electrodynamics are studied. The irrotational and solenoidal parts of the electric field are associated with two physically distinct types of sources. Relativistic covariance and gauge invariance in electromagnetic theory are reviewed and discussed in the context of an approach in which the mathematical properties of vector fields are taken as primary concepts. Special attention is given to the use and interpretation of the Coulomb gauge potential functions. This choice of gauge is sometimes regarded with undue suspicion, possibly because of a certain paradox concerning causality. The paradox is discussed and resolved. Useful properties of the Coulomb gauge are identified. These need not be limited to the case of slow time variations and can extend beyond the limits of validity of ideal MHD theory.

  6. The low-energy plasma in the Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Belcher, J. W.

    1983-01-01

    Burke and Franklin (1955) discovered radio emissions from Jupiter at 22.2 MHz. Subsequent observations established the strong control of the decametric emissions by the satellite Io. The Voyager encounters with Jupiter in 1979 have resulted in a dramatic increase in detailed knowledge of the plasma properties of the Jovian magnetosphere. The Io plasma torus is discussed, taking into account the Voyager plasma science experiment, positive-ion temperatures in the torus, electron distribution functions in the torus, elementary-charge concentrations in the torus, positive-ion composition in the torus, and plasma velocities in the torus. The Io flux tube is considered along with the middle magnetosphere and the outer magnetosphere. Attention is given to the sources of plasma, aspects of diffusive transport, questions of inertial loading, and the existence of nonazimuthal flow velocities in the middle magnetosphere.

  7. Plasma-neutral interaction processes in the magnetosphere of Saturn

    NASA Technical Reports Server (NTRS)

    Eviatar, Aharon

    1992-01-01

    Models of Saturnian magnetospheric processes are reviewed emphasizing the interaction of charged and neutral particles in the gaseous phase and mentioning the role of solid matter. It is found that interpretations of different Voyager datasets regarding the Saturnian magnetosphere can vary. Specific interactions examined to resolve these discrepancies include charge exchange, ion-atom interchange, isotropizing and thermalizing collisions, and interactions between magnetospheric charged particles and surface layers of the icy satellites. The latter interactions result in sputtering of the surface or atmosphere as well as neutral injections into the magnetosphere. Constraints based on known reaction rates are shown to be useful in analyzing the abundances of the water-group molecules. The composition of the magnetospheric plasma is shown to be related to the differences between the interactions of atomic and molecular plasmas with neutral matter.

  8. Magnetospheric and auroral plasmas - A short survey of progress

    NASA Technical Reports Server (NTRS)

    Frank, L. A.

    1975-01-01

    Important milestones in our researches of auroral and magnetospheric plasmas for the past quadrennium 1971-1975 are reviewed. Many exciting findings, including those of the polar cusp, the polar wind, the explosive disruptions of the magnetotail, the interactions of hot plasmas with the plasmapause, the auroral field-aligned currents, and the striking inverted V electron precipitation events, were reported during this period. Solutions to major questions concerning the origins and acceleration of these plasmas appear possible in the near future. A comprehensive bibliography of current research is appended to this brief survey of auroral and magnetospheric plasmas.

  9. Laboratory simulation of energetic flows of magnetospheric planetary plasma

    NASA Astrophysics Data System (ADS)

    Shaikhislamov, I. F.; Posukh, V. G.; Melekhov, A. V.; Boyarintsev, E. L.; Zakharov, Yu P.; Prokopov, P. A.; Ponomarenko, A. G.

    2017-01-01

    Dynamic interaction of super-sonic counter-streaming plasmas moving in dipole magnetic dipole is studied in laboratory experiment. First, a quasi-stationary flow is produced by plasma gun which forms a magnetosphere around the magnetic dipole. Second, explosive plasma expanding from inner dipole region outward is launch by laser beams focused at the surface of the dipole cover. Laser plasma is energetic enough to disrupt magnetic field and to sweep through the background plasma for large distances. Probe measurements showed that far from the initially formed magnetosphere laser plasma carries within itself a magnetic field of the same direction but order of magnitude larger in value than the vacuum dipole field at considered distances. Because no compression of magnetic field at the front of laser plasma was observed, the realized interaction is different from previous experiments and theoretical models of laser plasma expansion into uniform magnetized background. It was deduced based on the obtained data that laser plasma while expanding through inner magnetosphere picks up a magnetized shell formed by background plasma and carries it for large distances beyond previously existing magnetosphere.

  10. Imaging the earth's magnetosphere - Effects of plasma flow and temperature

    NASA Technical Reports Server (NTRS)

    Garrido, D. E.; Smith, R. W.; Swift, D. S.; Akasofu, S.-I.

    1991-01-01

    The effects of Doppler shifting on the line centers of the magnetospheric O(+) cross section are investigated, and the resulting structure of the scattering rate as a function of bulk density is explained. Whereas the Doppler shifting frequently results in a decrease of the scattering rate, it is demonstrated that for certain drift speeds the overlap of the cross section and the solar intensity profile can lead to an increased rate, thus enhancing the relative brightness of the image above that obtained when v(p) is zero. Simulated images of the magnetosphere are obtained which are used to show quantitively how the magnetospheric image responds to variations in plasma drift speed and temperature. Changes in the brightness of the magnetospheric images also depend on the variability of the solar flux at 83.4 nm. In regions where there are plasma drifts, the brightness in the image is governed by the structure of the scattering rate, assuming a fixed temperature.

  11. Mini Magnetospheric Plasma Propulsion (M2P2)

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis; Winglee, Robert

    2000-01-01

    The M2P2 concept is based on the transfer of momentum from the solar wind to an artificial magnetic field structure like that naturally occurs at all magnetized planets in the Solar System, called the magnetosphere. The objectives of this program include the following: (1) Demonstrate artificial magnetospheric inflation through cold plasma filling in vacuum; (2) Demonstrate deflection of a surrogate solar wind by an artificial magnetosphere in the laboratory vacuum chamber; (3) Compare theoretical calculations for thrust forces with laboratory measurements; (4) Develop flight control algorithms for planning mission specific trajectories; and (5) Develop M2P2 system concept.

  12. Experiments on planar plasma flow switches at Los Alamos

    SciTech Connect

    Benage, J.F. Jr.; Wysocki, F.J.; Bowers, R.; Oona, H.

    1997-12-01

    The authors have performed a series of experiments on the Colt facility at Los Alamos to study the performance of plasma flow switches and to understand the important physics issues which affect that performance. These experiments were done in planar geometry on a small machine to allow for better diagnostic access and a higher repetition rate. The Colt facility is a capacitor bank which stores 300 kJ at maximum charge and produced a peak current of 1.1 MA in 2.0 microseconds for these experiments. The diagnostics used for these experiments included an array of b-dot probes, visible framing pictures, visible spectroscopy, and laser interferometry. Characteristics of the switch are determined from spatial and temporal profiles of the magnetic field and the spatial profile and temperature of the switch plasma. Here the authors present results from experiments for a variety of switch conditions.

  13. Jupiter's Magnetosphere: Plasma Description from the Ulysses Flyby.

    PubMed

    Bame, S J; Barraclough, B L; Feldman, W C; Gisler, G R; Gosling, J T; McComas, D J; Phillips, J L; Thomsen, M F; Goldstein, B E; Neugebauer, M

    1992-09-11

    Plasma observations at Jupiter show that the outer regions of the Jovian magnetosphere are remarkably similar to those of Earth. Bow-shock precursor electrons and ions were detected in the upstream solar wind, as at Earth. Plasma changes across the bow shock and properties of the magnetosheath electrons were much like those at Earth, indicating that similar processes are operating. A boundary layer populated by a varying mixture of solar wind and magnetospheric plasmas was found inside the magnetopause, again as at Earth. In the middle magnetosphere, large electron density excursions were detected with a 10-hour periodicity as planetary rotation carried the tilted plasma sheet past Ulysses. Deep in the magnetosphere, Ulysses crossed a region, tentatively described as magnetically connected to the Jovian polar cap on one end and to the interplanetary magnetic field on the other. In the inner magnetosphere and lo torus, where corotation plays a dominant role, measurements could not be made because of extreme background rates from penetrating radiation belt particles.

  14. Characterization of Magnetospheric Spacecraft Charging Environments Using the LANL Magnetospheric Plasma Analyzer Data Set

    NASA Technical Reports Server (NTRS)

    Hardage, Donna (Technical Monitor); Davis, V. A.; Mandell, M. J.; Thomsen, M. F.

    2003-01-01

    An improved specification of the plasma environment has been developed for use in modeling spacecraft charging. It was developed by statistically analyzing a large part of the LANL Magnetospheric Plasma Analyzer (MPA) data set for ion and electron spectral signature correlation with spacecraft charging, including anisotropies. The objective is to identify a relatively simple characterization of the full particle distributions that yield an accurate predication of the observed charging under a wide variety of conditions.

  15. Ground-based ULF methods of monitoring the magnetospheric plasma

    NASA Astrophysics Data System (ADS)

    Romanova, Natalia; Pilipenko, Viacheslav; Stepanova, Marina; Kozyreva, Olga; Kawano, Hideaki

    The terrestrial magnetosphere is a giant natural MHD resonator. The magnetospheric Alfven resonator is formed by the geomagnetic field lines terminated by the conductive ionospheres. Though a source of Pc3-5 waves is not reliably known, the identification of resonant frequency enables one to determine the magnetospheric plasma density and ionospheric conductance from ground magnetometer observations. However, a spectral peak does not necessarily correspond to a local resonant frequency, and the width of a spectral peak cannot be directly used to determine the quality factor of the magnetospheric resonator. This ambiguity can be resolved with the help of various gradient and polarization methods, reviewed in this presentation: Gradient method (GM), Amplitude-Phase Gradient method (APGM),Polarization methods (including H/D method), and Hodograph (H) method. These methods can be regarded as tools for the "hydromagnetic spectroscopy“ to diagnose the magnetosphere. The H-method has additional possibilities as compared with the gradient method: one can determine continuous distribution of the magnetospheric resonant frequencies and Q-factors in the range of latitudes beyond the observation baseline. These methods are illustrated by results of their application to the SAMBA magnetometers array data.

  16. Voyager 2 plasma ion observations in the magnetosphere of Uranus

    NASA Technical Reports Server (NTRS)

    Selesnick, Richard S.; Mcnutt, Ralph L., Jr.

    1987-01-01

    Positive ion measurements in the magnetosphere of Uranus have been made by the Voyager 2 plasma science experiment. The paper presents an overview of the entire data set and a detailed analysis of the observations from the inner magnetosphere which complements and extends results reported elsewhere. Densities and temperatures are obtained from an analysis which incorporates details of the instrumental response. These results are then used to calculate flux tube particle and energy content to support the hypothesis that the plasma transport is controlled by a solar wind-driven magnetospheric convection system. Variations in the flux tube content suggest both a local source of plasma, produced from the neutral hydrogen corona of Uranus, and a nonlocal source, convected inwared and heated by adiabatic compression. In each case a proton composition is inferred. Sharp boundaries in the high-energy (approximately 1 keV) plasma population are interpreted in terms of the spatial extent of the magnetospheric convection, with significant shielding of the convection electric field. The convection theory is also used in a simulation of the low-energy (approximately 10 eV) ion component using the neutral hydrogen source, resulting in distribution functions which qualitatively agree with the observations.

  17. Cross-Frequency Coupling of Plasma Waves in the Magnetosphere

    NASA Astrophysics Data System (ADS)

    Khazanov, G. V.

    2014-12-01

    Wave-particle and wave-wave interactions are crucial elements of magnetosphere and ionosphere plasma dynamics. Such interactions provide a channel of energy redistribution between different plasma populations, and lead to connections between physical processes developing on different spatial and temporal scales. The lower hybrid waves (LHWs) are particularly interesting for plasma dynamics, because they couple well with both electrons and ions. The excitation of LHWs is a widely discussed mechanism of interaction between plasma species in space and is one of the unresolved questions of magnetospheric multi-ion plasmas. It is demonstrated that large-amplitude Alfven and/or EMIC waves, in particular those associated with lower frequency (LF) turbulence, may generate LHWs in the auroral zone and ring current region and in some cases this serves as the Alfven and/or EMIC waves saturation mechanism. We believe that this described scenario, as well as some other cross-frequency coupling of plasma waves processes that will be discussed in this presentation, can play a vital role in various parts of the magnetospheric plasma, especially in the places under investigation by the NASA THEMIS and Van Allen Probes (formerly known as the Radiation Belt Storm Probes (RBSP)) missions.

  18. The Fast Plasma Investigation on the Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Rager, A. C.; Pollock, C. J.; Avanov, L. A.; Barrie, A. C.; Burch, J. L.; Chandler, M. O.; Clark, G. B.; Coffey, V. N.; Dickson, C.; Dorelli, J.; Ergun, R.; Fuselier, S. A.; Gliese, U.; Giles, B. L.; Holland, M. P.; Jacques, A. D.; Kreisler, S.; Lavraud, B.; MacDonald, E.; Mauk, B.; Moore, T. E.; Mukai, T.; Nakamura, R.; Rosnack, T.; Saito, Y.; Salo, C.; Sauvaud, J. A.; Smith, D. L.; Smith, S. E.; Torbert, R. B.; Yokota, S.

    2015-12-01

    Launched in March 2015, the Fast Plasma Investigation (FPI) instrument suite on the Magnetospheric Multiscale Mission (MMS) is producing the highest time and spatial resolution 3D electron and ion particle distribution function measurements to date. During FPI science operations, the four spacecraft maintain a tetrahedral formation such that 3D measurements of the plasma and field gradients are enabled. This allows the spacecraft to better investigate reconnection and to distinguish between spatial and temporal structures. In the first three months, we expect to observe magnetic phenomena such as dipolarization fronts, the plasma sheet boundary layer, magnetopause crossings, ion dispersive signatures of from remote reconnection sites, and magnetic holes. This poster is intended to supplement the invited talk on FPI results by Pollock et al. by providing further detail of the instrumentation and calibration, as well as a sampling of early magnetospheric plasma observations in the evening-side magnetotail, dusk flank, and afternoon magnetopause.

  19. Quantitative Simulation of a Magnetospheric Substorm. 2. Comparison with Observations,

    DTIC Science & Technology

    1980-01-23

    we overestimated the polar-boundary potential drop; consequently the p) asma -sheet ions were injected deeper into the magnetosphere than was the case...Magnetospheric Substorms and Related Plasma Processes, Los Alamos, New Mexico , October 1978 and to be published in Astrophysics and Space Science Library...and Related Plasma Processes, Los Alamos, New Mexico , October 1978, published in Astrophysics and Space Science Library Series,p.14 3, Yasuhara, F., and

  20. Recirculation and Acceleration of Ionospheric Plasma in the Martian Magnetospheres

    NASA Astrophysics Data System (ADS)

    Ip, Wing-Huen

    2012-07-01

    The presence of strong crustal remnant magnetic fields on Mars has important influence on the dynamical behavior of the ionospheric plasma. A model based on computational simulation of the time-varying configuration of the mini-magnetosphere is described to examine the possible process of acceleration and heating of photo electrons and ions embedded in the magnetic flux tubes as Mars rotates from dawn to dusk. The main idea is that ionospheric H+ and O+ ions pumped into the mini-magnetospheres on the dawn side could be subject to adiabatic heating during "depolarization" of the magnetic field as the local time approaches noon.

  1. Low-energy plasma observations in the magnetosphere of Uranus

    NASA Technical Reports Server (NTRS)

    Mcnutt, Ralph L., Jr.; Selesnick, Richard S.; Richardson, John D.

    1987-01-01

    The large, low density plasma-containing magnetosphere detected at Uranus by Voyager 2 appears to be primarily composed of protons and electrons. On a long time scale, the protons are apparently transported from the planet's nightside to the dayside by a convective electric field that is generated by the solar wind. The time for the particles to convect through the Uranian magnetosphere is estimated to be about 1 week. The proton distribution functions are characterized by a warm, subsonic core and a non-Maxwellian tail that varies significantly along the spacecraft trajectory.

  2. A quantitative model of plasma in Neptune's magnetosphere

    NASA Astrophysics Data System (ADS)

    Richardson, J. D.

    1993-07-01

    A model encompassing plasma transport and energy processes is applied to Neptune's magnetosphere. Starting with profiles of the neutral densities and the electron temperature, the model calculates the plasma density and ion temperature profiles. Good agreement between model results and observations is obtained for a neutral source of 5 x 10 exp 25/s if the diffusion coefficient is 10 exp -8 L3R(N)/2s, plasma is lost at a rate 1/3 that of the strong diffusion rate, and plasma subcorotates in the region outside Triton.

  3. Observations of Magnetic Reconnection and Plasma Dynamics in Mercury's Magnetosphere

    NASA Astrophysics Data System (ADS)

    DiBraccio, Gina A.

    Mercury's magnetosphere is formed as a result of the supersonic solar wind interacting with the planet's intrinsic magnetic field. The combination of the weak planetary dipole moment and intense solar wind forcing of the inner heliosphere creates a unique space environment, which can teach us about planetary magnetospheres. In this work, we analyze the first in situ orbital observations at Mercury, provided by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Magnetic reconnection and the transport of plasma and magnetic flux are investigated using MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer measurements. Here, we report our results on the effect of magnetic reconnection and plasma dynamics on Mercury's space environment: (1) Mercury's magnetosphere is driven by frequent, intense magnetic reconnection observed in the form of magnetic field components normal to the magnetopause, BN, and as helical bundles of flux, called magnetic flux ropes, in the cross-tail current sheet. The high reconnection rates are determined to be a direct consequence of the low plasma beta, the ratio of plasma to magnetic pressure, in the inner heliosphere. (2) As upstream solar wind conditions vary, we find that reconnection occurs at Mercury's magnetopause for all orientations of the interplanetary magnetic field, independent of shear angle. During the most extreme solar wind forcing events, the influence of induction fields generated within Mercury's highly conducting core are negated by erosion due to persistent magnetopause reconnection. (3) We present the first observations of Mercury's plasma mantle, which forms as a result of magnetopause reconnection and allows solar wind plasma to enter into the high-latitude magnetotail through the dayside cusps. The energy dispersion observed in the plasma mantle protons is used to infer the cross-magnetosphere electric field, providing a direct measurement of solar wind momentum

  4. Investigating Fresh Hot Plasma Injections in Saturn's Inner-Magnetosphere

    NASA Astrophysics Data System (ADS)

    Vandegriff, J. D.; Loftus, K.; Rymer, A. M.; Mitchell, D. G.

    2015-12-01

    A decreasing density gradient in Saturn's plasma disk allows for centrifugal interchange instability between the dense, heavy plasma inside 10 Rs and the lighter plasma outside. This instability results in the less dense plasma of the mid-magnetosphere moving inward to the inner-magnetosphere. As flux tubes move inward, their volume decreases, and the contained plasma heats adiabatically. Most studies of interchange have focused on older events that have had time to gradient and curvature drift such that they are easily identified by a characteristic "V" energy dispersion signature in the ion and electron data [e.g. Hill et al., 2005; Chen et al., 2010]. Recently, Kennelly et al. (2013) used radio wave data to identify >300 possible "fresh" injection events. These are characterized in the plasma data by a bite-out at low energies, an enhancement at high energies, and little to no energy dispersion. Our study builds on the Kennelly et al. study to investigate the shape and frequency of injection events in order to better characterize how hot plasma transports into the inner magnetosphere. In most models of centrifugal interchange at Saturn, the time and spatial scales for inward and outward transport are fairly symmetric, but Cassini data suggests that inward injections of plasma move at much greater velocity and in narrower flow channels than their outgoing counterparts. Here we investigate the morphology of Kronian inward injection events to see if our dataset of young injections can inform on whether the inward injections are extended fingers or more like "bubbles", isolated flux tubes. Specifically, we apply minimum variance analysis to Cassini magnetic field data to determine the boundary normals at the spacecraft's entrance and exit points for each event, from which we can statistically analyze the structure's cross section. We will present our initial results on the morphology as well as the distribution of the injections over radial distance, latitude, and

  5. Solar wind electrons as tracers of magnetospheric boundaries and plasma processes within the Martian magnetosphere

    NASA Astrophysics Data System (ADS)

    Dubinin, Eduard

    Electrons with energy of 40-80eV measured by the instrument ASPERA-3 on Mars Express and MAG-ER onboard Mars Global Surveyor are used to trace an access of solar wind electrons into the Martian magnetosphere. Crustal magnetic fields create an additional protection from solar wind plasma on the dayside of the southern hemisphere by shifting the magnetospheric boundary above strong crustal sources to ˜ 400 - 500 km as compared to the northern hemisphere. Localized intrusions through cusps are also observed. On the nightside an access into the magnetosphere depends on the IMF orientation. Negative values of the ByIM F component assist the access to the regions with strong crustal magnetizations although electron fluxes are strongly weakened below ˜ 600 km. A precipitation pattern at lower altitudes is formed by intermittent regions with reduced and enhanced electron fluxes. The precipitation sites are longitudinally stretched narrow bands in the regions with a strong vertical component of the crustal field. Fluxes ≥ 109 cm-2 s-1 of suprathermal electrons necessary to explain the observed aurora emissions are maintained only for the periods with enhanced precipitation. The appearance of another class of electron distributions - inverted V structures, characterized by peaks on energy spectra, is controlled by the IMF. They are clustered in the hemisphere pointed by the interplanetary electric field that implies a constraint on their origin.

  6. Evidence for rotationally driven plasma transport in Saturn's magnetosphere

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Rymer, A. M.; Burch, J. L.; Crary, F. J.; Young, D. T.; Thomsen, M. F.; Delapp, D.; André, N.; Coates, A. J.; Lewis, G. R.

    2005-06-01

    Radial convective transport of plasma in a rotation-dominated magnetosphere implies alternating longitudinal sectors of cooler, denser plasma moving outward and hotter, more tenuous plasma moving inward. The Cassini Plasma Spectrometer (CAPS) has provided dramatic new evidence of this process operating in the magnetosphere of Saturn. The inward transport of hot plasma is accompanied by adiabatic gradient and curvature drift, producing a V-shaped dispersion signature on a linear energy-time plot. Of the many (~100) such signatures evident during the first two Cassini orbits, we analyze a subset (48) that are sufficiently isolated to allow determination of their ages, widths, and injection locations. Ages are typically <10.8 hr (Saturn's rotation period) but range up to several rotation periods. Widths are typically <1 RS (Saturn's radius) but range up to several RS. Injection locations are randomly distributed in local time and in Saturnian longitude. The apex of the V sometimes coincides with a localized density cavity in the cooler background plasma, and usually coincides with a localized diamagnetic depression of the magnetic field strength. These signatures are fully consistent with the convective motions that are expected to result from the centrifugal interchange instability.

  7. Penetration of Magnetosheath Plasma into Dayside Magnetosphere. 2. ; Magnetic Field in Plasma Filaments

    NASA Technical Reports Server (NTRS)

    Lyatsky, Wladislaw; Pollock, Craig; Goldstein, Melvyn L.; Lyatskaya, Sonya Inna; Avanov, Levon Albert

    2016-01-01

    In this paper, we examined plasma structures (filaments), observed in the dayside magnetosphere but containing magnetosheath plasma. These filaments show the stable antisunward motion (while the ambient magnetospheric plasma moved in the opposite direction) and the existence of a strip of magnetospheric plasma, separating these filaments from the magnetosheath. These results, however, contradict both theoretical studies and simulations by Schindler (1979), Ma et al. (1991), Dai and Woodward (1994, 1998), and other researchers, who reported that the motion of such filaments through the magnetosphere is possible only when their magnetic field is directed very close to the ambient magnetic field, which is not the situation that is observed. In this study, we show that this seeming contradiction may be related to different events as the theoretical studies and simulations are related to the case when the filament magnetic field is about aligned with filament orientation, whereas the observations show that the magnetic field in these filaments may be rotating. In this case, the rotating magnetic field, changing incessantly its direction, drastically affects the penetration of plasma filaments into the magnetosphere. In this case, the filaments with rotating magnetic field, even if in each moment it is significantly inclined to the ambient magnetic field, may propagate through the magnetosphere, if their average (for the rotation period) magnetic field is aligned with the ambient magnetic field. This shows that neglecting the rotation of magnetic field in these filaments may lead to wrong results.

  8. Low-Energy Hot Plasma and Particles in Saturn's Magnetosphere.

    PubMed

    Krimigis, S M; Armstrong, T P; Axford, W I; Bostrom, C O; Gloeckler, G; Keath, E P; Lanzerotti, L J; Carbary, J F; Hamilton, D C; Roelof, E C

    1982-01-29

    The low-energy charged particle instrument on Voyager 2 measured low-energy electrons and ions (energies greater, similar 22 and greater, similar 28 kiloelectron volts, respectively) in Saturn's magnetosphere. The magnetosphere structure and particle population were modified from those observed during the Voyager 1 encounter in November 1980 but in a manner consistent with the same global morphology. Major results include the following. (i) A region containing an extremely hot ( approximately 30 to 50 kiloelectron volts) plasma was identified and extends from the orbit of Tethys outward past the orbit of Rhea. (ii) The low-energy ion mantle found by Voyager 1 to extend approximately 7 Saturn radii inside the dayside magnetosphere was again observed on Voyager 2, but it was considerably hotter ( approximately 30 kiloelectron volts), and there was an indication of a cooler ( < 20 kiloelectron volts) ion mantle on the nightside. (iii) At energies greater, similar 200 kiloelectron volts per nucleon, H(1), H(2), and H(3) (molecular hydrogen), helium, carbon, and oxygen are important constituents in the Saturnian magnetosphere. The presence of both H(2) and H(3) suggests that the Saturnian ionosphere feeds plasma into the magnetosphere, but relative abundances of the energetic helium, carbon, and oxygen ions are consistent with a solar wind origin. (iv) Low-energy ( approximately 22 to approximately 60 kiloelectron volts) electron flux enhancements observed between the L shells of Rhea and Tethys by Voyager 2 on the dayside were absent during the Voyager 1 encounter. (v) Persistent asymmetric pitch-angle distributions of electrons of 60 to 200 kiloelectron volts occur in the outer magnetosphere in conjunction with the hot ion plasma torus. (vi) The spacecraft passed within approximately 1.1 degrees in longitude of the Tethys flux tube outbound and observed it to be empty of energetic ions and electrons; the microsignature of Enceladus inbound was also observed. (vii

  9. Hot-cold plasma interactions in the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Williams, D. J.

    1975-01-01

    The paper gives a synopsis of observations and results obtained from the Explorer-45 satellite which pertain directly to the interaction of the magnetospheric hot and cold plasma populations. The specific case discussed is the interaction of the hot ring current plasma with the cold plasmaspheric plasma in the evening to early morning local time sector during magnetic storm recovery phase. It was found that above the plasmapause region, the hot ring current plasma is stable with negligible losses due to pitch angle diffusion; the hot ring current plasma enters a moderate pitch angle regime in the plasmapause region, whereby the addition of cold plasma destabilizes the hot plasma. Analysis of the energy, spatial, and temporal dependence of the above destabilization along with the ion-cyclotron resonant energy equation, and comparison of this analysis with an in situ estimate of the plasma density strongly indicate that the mechanism responsible for destabilization of the hot plasma is the amplification of ion-cyclotron waves due to the interaction of the cold plasmaspheric plasma with the hot ring current plasma in a manner similar to that discussed by Cornwall et al. (1970).

  10. Plasma Transport at the Magnetospheric Flank Boundary. Final report

    SciTech Connect

    Otto, Antonius

    2012-04-23

    Progress is highlighted in these areas: 1. Model of magnetic reconnection induced by three-dimensional Kelvin Helmholtz (KH) modes at the magnetospheric flank boundary; 2. Quantitative evaluation of mass transport from the magnetosheath onto closed geomagnetic field for northward IMF; 3. Comparison of mass transfer by cusp reconnection and Flank Kelvin Helmholtz modes; 4. Entropy constraint and plasma transport in the magnetotail - a new mechanism for current sheet thinning; 5. Test particle model for mass transport onto closed geomagnetic field for northward IMF; 6. Influence of density asymmetry and magnetic shear on (a) the linear and nonlinear growth of 3D Kelvin Helmholtz (KH) modes, and (b) three-dimensional KH mediated mass transport; 7. Examination of entropy and plasma transport in the magnetotail; 8. Entropy change and plasma transport by KH mediated reconnection - mixing and heating of plasma; 9. Entropy and plasma transport in the magnetotail - tail reconnection; and, 10. Wave coupling at the magnetospheric boundary and generation of kinetic Alfven waves.

  11. The magnetosphere of uranus: hot plasma and radiation environment.

    PubMed

    Krimigis, S M; Armstrong, T P; Axford, W I; Cheng, A F; Gloeckler, G; Hamilton, D C; Keath, E P; Lanzerotti, L J; Mauk, B H

    1986-07-04

    The low-energy charged-particle (LECP) instrument on Voyager 2 measured lowenergy electrons and ions near and within the magnetosphere of Uranus. Initial analysis of the LECP measurements has revealed the following. (i) The magnetospheric particle population consists principally of protons and electrons having energies to at least 4 and 1.2 megaelectron volts, respectively, with electron intensities substantially excceding proton intensities at a given energy. (ii) The intensity profile for both particle species shows evidence that the particles were swept by planetry satellites out to at least the orbit of Titania. (iii) The ion and electron spectra may be described by a Maxwellian core at low energies (less than about 200 kiloelectron volts) and a power law at high energies (greater than about 590 kiloelectron volts; exponentmicro, 3 to 10) except inside the orbit of Miranda, where power-law spectra (micro approximately 1.1 and 3.1 for electrons and protons, respectively) are observed. (iv) At ion energies between 0.6 and 1 megaelectron volt per nucleon, the composition is dominated by protons with a minor fraction (about 10(-3)) of molecular hydrogen; the lower limit for the ratio of hydrogen to helium is greater than 10(4). (v) The proton population is sufficiently intense that fluences greater than 10(16) per square centimeter can accumulate in 10(4) to 10(') years; such fluences are sufficient to polymerize carbon monoxide and methane ice surfaces. The overall morphology of Uranus' magnetosphere resembles that of Jupiter, as evidenced by the fact that the spacecraft crossed the plasma sheet through the dawn magnetosheath twice per planetary rotation period (17.3 hours). Uranus' magnetosphere differs from that of Jupiter and of Saturn in that the plasma 1 is at most 0.1 rather than 1. Therefore, little distortion ofthe field is expected from particle loading at distances less than about 15 Uranus radii.

  12. MESSENGER Magnetometer Observations of the Plasma Distribution in Mercury's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Korth, H.; Anderson, B. J.; Raines, J. M.; Slavin, J. A.; Johnson, C. L.; Purucker, M. E.; Winslow, R. M.; Zurbuchen, T.; Solomon, S. C.; McNutt, R. L.

    2011-12-01

    Since insertion of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft into orbit around Mercury on 18 March 2011, the Magnetometer (MAG) has routinely observed localized reductions of the magnetic field magnitude below the level predicted by a planetary dipole model corrected for magnetospheric magnetic fields. These magnetic depressions are observed on almost every orbit, and the latitude at which they are observed is local-time dependent. The depression signatures are indicators for the presence of enhanced plasma populations, which inflate the magnetic field locally to maintain pressure balance, thus lowering the magnetic flux density. Mapping the magnetic depressions in local time and latitude, the MAG observations provide comprehensive insight into the plasma distribution near the planet, which is complementary to that provided by MESSENGER's Fast Imaging Plasma Spectrometer (FIPS). The spatial distribution shows that magnetic depressions are concentrated in two distinct regions. First, there is a population in the nightside equatorial region extending from dusk to dawn, which is offset northward from the planetary geographic equator by about 10°, commensurate with the offset of the planetary dipole. The extent of this population is indicative of the plasma sheet located in the equatorial magnetotail. A second concentration of magnetic depressions is found at high latitudes, predominantly on the dayside, and is associated with the magnetospheric cusp. The magnitude of the pressures associated with the depressions ranges from 0.1 to 3 nPa in the equatorial region, shows a systematic gradient from dusk to dawn, and reaches 10 nPa at high latitudes. We discuss the MAG observations and interpret the dusk-to-dawn gradient in the derived pressure distribution with a simple paradigm of particle drifts within Mercury's magnetosphere.

  13. Plasma Speeds Upstream of Saturn and in the Magnetosphere as Measured by Cassini's Magnetospheric Imaging Instrument (MIMI)

    NASA Astrophysics Data System (ADS)

    Vandegriff, J. D.; Hill, M. E.; Gloeckler, G.; Hamilton, D. C.; Kane, M.; Krimigis, S. M.; Mitchell, D. G.; Steinberg, J. T.; Tao, C.; Thomsen, M. F.

    2014-12-01

    Knowledge of plasma speeds inside Saturn's magnetosphere and in the upstream solar wind is important for developing a complete picture of magnetospheric processes at Saturn. Therefore we have developed techniques for extracting plasma speeds from these environments using data from the Magnetospheric Imaging Instrument (MIMI) on Cassini. The Cassini Plasma Spectrometer (CAPS) also measures the plasma speed and other properties, and we rely on CAPS results to validate our approach. However, there are some intervals during which MIMI is oriented more favorably in terms of detecting ambient plasma flows. Furthermore, CAPS operations have ceased, and MIMI provides an alternative way to measure plasma characteristics. In the solar wind, the plasma speed can be determined directly from MIMI's Charge-Energy-Mass Spectrometer (CHEMS) using the easily observable cutoff in He+ pickup ion (PUI) spectra, because there is a well-known relationship between this PUI cutoff and the ambient solar wind speed. PUIs are distributed over a wide angular extent, and thus CHEMS can obtain solar wind speeds at times when CAPS does not see the direct solar wind ions. We present solar wind speeds derived in this way from 2001 to 2004, a period that includes most of the interplanetary cruise preceding the mid-2004 Saturn orbit insertion (SOI) and the long post-SOI loop back into the solar wind. These values show good agreement with CAPS measurements available during the same interval and with a solar wind propagation model. Inside Saturn's magnetosphere, we are using a combination of data from CHEMS and MIMI's Ion and Neutral Camera (INCA) to derive speeds based on anisotropies. CAPS measurements in the magnetosphere are used to validate the MIMI-based speeds, but it is also possible to use our technique for periods when CAPS cannot be used to measure plasma velocities directly. We will present initial results of magnetospheric speeds from 2004 to the present.

  14. The magnetosphere of Uranus - Hot plasma and radiation environment

    NASA Technical Reports Server (NTRS)

    Krimigis, S. M.; Armstrong, T. P.; Axford, W. I.; Cheng, A. F.; Gloeckler, G.

    1986-01-01

    Inferences are drawn on the morphology and composition of the Uranus magnetosphere based on low-energy charged particle data collected by Voyager 2. Proton and electron energies in the magnetosphere attained energies of 4 and 1.2 MeV, respectively, although electron intensities surpassed the proton intensities at most energy levels. Protons dominated in the ion energy regime 0.6-1.0 MeV. The ion and electron spectra were Maxwellian below about 200 keV and had a power law distribution at energies over 590 keV. The power law was reduced by a factor of nearly three inside the orbit of Miranda. The proton population is dense enough to polymerize CO and CH4 ice surfaces within 10,000-100,000 yr. The data indicated that the particles are swept out at least to the orbit of Titania by the satellites. The morphology of the magnetosphere closely resembles that around Jupiter, except that plasma sheet distorsion from particle loading is negligible in regions within 15 Uranus radii.

  15. Thermal and suprathermal plasma densities in the outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Frank, L. A.

    1973-01-01

    Using the low-frequency cutoff of electromagnetic noise trapped in the magnetosphere at frequencies above the local plasma frequency, it is now possible to make very accurate, + or - 1%, electron density measurements in the low density region between the magnetopause and plasmapause. This technique for measuring the total plasma density was used, together with measurements of the suprathermal proton intensities with the LEPEDEA instrumentation on the IMP-6 spacecraft, to determine the thermal proton densities in the region between the plasmapause and magnetopause. Although the thermal protons usually account for a significant fraction, approximately 50%, of the total proton density in this region, in some cases, particularly at the larger radial distances the density of the thermal protons sometimes drops to a very small fraction, 5%, of the total density and nearly all of the plasma consists of suprathermal particles.

  16. Flute instability in the plasma shell of the earth's magnetosphere

    SciTech Connect

    Ivanov, V.N.; Pokhotelov, O.A.

    1987-12-01

    In the plasma shell of the earth's magnetosphere, the surfaces of constant pressure may not coincide with surfaces of constant specific volume. This circumstance forces a reexamination of the theory for the flute instability, in which the pressure has been assumed to remain constant on surfaces of constant specific volume. The MHD equations for flute waves in a curvilinear magnetic field are used to show that an instability of a new type, with a pressure which does not remain constant on surfaces of constant specific volume, can occur in the plasma shell of the magnetosphere. An expression is derived for the growth rate of this instability. Analysis of the equation also shows that perturbations with wavelengths shorter than the ion Larmor radius are stable by virtue of magnetodrift effects. The growth rates of the flute instabilities are calculated for both a dipole magnetic field and an arbitrary magnetic-field configuration. Growth rates calculated for typical values of the characteristics of the earth's plasma shell are reported.

  17. Los Alamos x-ray characterization facilities for plasma diagnostics

    SciTech Connect

    Day, R.H.; Blake, R.L.; Stradling, G.L.; Trela, W.J.; Bartlett, R.J.

    1986-01-01

    A summary is given of characteristics of x-ray sources used by Los Alamos National Laboratory to calibrate various x-ray diagnostic packages and components. Included are D.C. sourcs in electron impact and fluorescence modes, a pulsed laser source for soft x rays with 100 ps time resolution, Febetron pulsed electron impact sources, and both EUV and x-ray synchrotron beamlines.

  18. Ion-cyclotron turbulence and diagonal double layers in a magnetospheric plasma

    NASA Technical Reports Server (NTRS)

    Liperovskiy, V. A.; Pudovkin, M. I.; Skuridin, G. A.; Shalimov, S. L.

    1981-01-01

    A survey of current concepts regarding electrostatic ion-cyclotron turbulence (theory and experiment), and regarding inclined double potential layers in the magnetospheric plasma is presented. Anomalous resistance governed by electrostatic ion-cyclotron turbulence, and one-dimensional and two-dimensional models of double electrostatic layers in the magnetospheric plasma are examined.

  19. The Earth's magnetosphere as a sample of the plasma universe

    NASA Technical Reports Server (NTRS)

    Faelthammar, Carl-Gunne

    1986-01-01

    Plasma processes in the Earth's neighborhood determine the environmental conditions under which space-based equipment for science or technology must operate. These processes are peculiar to a state of matter that is rare on Earth but dominates the universe as whole. The physical, and especially the electrodynamic, properties of this state of matter is still far from well understood. By fortunate circumstances, the magnetosphere-ionosphere system of the Earth provides a rich sample of widely different plasma populations, and, even more importantly, it is the site of a remarkable variety of plasma processes. In different combinations such processes must be important throughout the universe, which is overwhelmingly dominated by matter in the plasma state. Therefore, observations and experiments in the near-Earth plasma serve a multitude of purposes. They will not only (1) clarify the dynamics of the space environment but also (2) widen the understanding of matter, (3) form a basis for interpretating remote observations of astrophysical objects, thereby even (4) help to reconstruct events that led to the evolution of the solar system. Last but not least they will (5) provide know-how required for adapting space-based technology to the plasma environment. Such observations and experiments will require a close mutual interplay between science and technology.

  20. On the generation of plasma waves in Saturn's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Barbosa, D. D.; Kurth, W. S.

    1993-06-01

    Voyager 1 plasma wave measurements of Saturn's inner magnetosphere are reviewed with regard to interpretative aspects of the wave spectrum. A comparison of the wave emission profile with the electron plasma frequency obtained from in situ measurements of the thermal ion density shows good agreement with various features in the wave data identified as electrostatic modes and electromagnetic radio waves. Theoretical calculations of the critical flux of superthermal electrons able to generate whistler-mode waves and electrostatic electron cyclotron harmonic waves through a loss-cone instability are presented. The comparison of model results with electron measurements shows excellent agreement, thereby lending support to the conclusion that a moderate perpendicular anisotropy in the hot electron distribution is present in the equatorial region of L = 5-8.

  1. Electromagnetic radiation trapped in the magnetosphere above the plasma frequency

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Shaw, R. R.

    1973-01-01

    An electromagnetic noise band is frequently observed in the outer magnetosphere by the Imp 6 spacecraft at frequencies from about 5 to 20 kHz. This noise band generally extends throughout the region from near the plasmapause boundary to near the magnetopause boundary. The noise typically has a broadband field strength of about 5 microvolts/meter. The noise band often has a sharp lower cutoff frequency at about 5 to 10 kHz, and this cutoff has been identified as the local electron plasma frequency. Since the plasma frequency in the plasmasphere and solar wind is usually above 20 kHz, it is concluded that this noise must be trapped in the low-density region between the plasmapause and magnetopause boundaries. The noise bands often contain a harmonic frequency structure which suggests that the radiation is associated with harmonics of the electron cyclotron frequency.

  2. Composition and dynamics of plasma in Saturn's magnetosphere.

    PubMed

    Young, D T; Berthelier, J-J; Blanc, M; Burch, J L; Bolton, S; Coates, A J; Crary, F J; Goldstein, R; Grande, M; Hill, T W; Johnson, R E; Baragiola, R A; Kelha, V; McComas, D J; Mursula, K; Sittler, E C; Svenes, K R; Szegö, K; Tanskanen, P; Thomsen, M F; Bakshi, S; Barraclough, B L; Bebesi, Z; Delapp, D; Dunlop, M W; Gosling, J T; Furman, J D; Gilbert, L K; Glenn, D; Holmlund, C; Illiano, J-M; Lewis, G R; Linder, D R; Maurice, S; McAndrews, H J; Narheim, B T; Pallier, E; Reisenfeld, D; Rymer, A M; Smith, H T; Tokar, R L; Vilppola, J; Zinsmeyer, C

    2005-02-25

    During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.

  3. Rotation Rate of Saturn's Magnetosphere using CAPS Plasma Measurements

    NASA Technical Reports Server (NTRS)

    Sittler, E.; Cooper, J.; Hartle, R.; Simpson, D.; Johnson, R.; Thomsen, M.; Arridge, C.

    2011-01-01

    We present the present status of an investigation of the rotation rate of Saturn's magnetosphere using a 3D velocity moment technique being developed at Goddard which is similar to the 2D version used by Sittler et al. for SOI and similar to that used by Thomsen et al.. This technique allows one to nearly cover the full energy range of the Cassini Plasma Spectrometer (CAPS) IMS from 1 V . E/Q < 50 kV. Since our technique maps the observations into a local inertial frame, it does work during roll maneuvers. We make comparisons with the bi-Maxwellian fitting technique developed by Wilson et al. and the similar velocity moment technique by Thomsen et al. . We concentrate our analysis when ion composition data is available, which is used to weight the non-compositional data, referred to as singles data, to separate H+, H2+ and water group ions (W+) from each other. The chosen periods have high enough telemetry rates (4 kbps or higher) so that coincidence ion data, similar to that used by Sittler et al. for SOI is available. The ion data set is especially valuable for measuring flow velocities for protons, which are more difficult to derive using singles data within the inner magnetosphere, where the signal is dominated by heavy ions (i.e., proton peak merges with W+ peak as low energy shoulder). Our technique uses a flux function, which is zero in the proper plasma flow frame, to estimate fluid parameter uncertainties. The comparisons investigate the experimental errors and potential for systematic errors in the analyses, including ours. The rolls provide the best data set when it comes to getting 4PI coverage of the plasma but are more susceptible to time aliasing effects. In the future we will then make comparisons with magnetic field observations, Saturn ionosphere conductivities as presently known and the field aligned currents necessary for the planet to enforce corotation of the rotating plasma.

  4. Jovian magnetospheric plasma effects at Europa and Ganymede (Invited)

    NASA Astrophysics Data System (ADS)

    Johnson, R. E.; Cassidy, T. A.; Hendrix, A. R.; Paranicas, C.; Cipriani, F.; Leblanc, F.; Cooper, J. F.

    2009-12-01

    Europa and Ganymede are imbedded in the Jovian magnetospheric plasma. This plasma alters their surfaces producing tenuous surface boundary-layer atmospheres (Johnson, 2002). That is, the interactions of the desorbed neutrals with the surface determine the composition and morphology of their atmospheres (Cassidy et al. 2009; Cipriani et al. 2009). Those neutrals that escape the satellite remain gravitationally bound to Jupiter in a toroidal-shaped cloud until they are ionized and contribute to the ambient plasma. Since gas-phase species are readily identified, the gravitationally bound and toroidal components are of interest as extensions of the satellite’s surface. If these atmospheres were only populated by thermal desorption, they would have a small subsolar water component (Shematovich et al. 2005) and the trace volatiles would be rapidly depleted. However, Europa and Ganymede orbit in a region of the Jovian magnetosphere in which the trapped plasma density and temperature are relatively high. This plasma and the solar EUV flux chemically alter and erode their surfaces, processes often lumped together as sputtering. Early laboratory results were used to predict the principal atmospheric component, O2, and its average column density (Johnson et al. 1982). Since loss of H2 accompanies the formation and ejection of O2 from ice (Johnson and Quickenden 1997), and, since H2 escapes more readily than the heavier species, hydrogen is a principal species in the neutral torus (Smyth and Marconi 2006) and a primary source of protons for the Jovian magnetosphere. Atmospheric simulations using models for the surface composition, data on the radiation flux, and laboratory data have been used in to interpret the available observations and to suggest which trace species might be detectable by an orbiting spacecraft. Models for the atmospheres of Europa and Ganymede and their relation to the plasma-weathered surfaces will be described in which redistribution and loss to the

  5. Rotation Rate of Saturn's Magnetosphere using CAPS Plasma Measurements

    NASA Technical Reports Server (NTRS)

    Sittler, E.; Cooper, J.; Simpson, D.; Paterson, W.

    2012-01-01

    We present the present status of an investigation of the rotation rate of Saturn 's magnetosphere using a 3D velocity moment technique being developed at Goddard which is similar to the 2D version used by Sittler et al. (2005) [1] for SOI and similar to that used by Thomsen et al. (2010). This technique allows one to nearly cover the full energy range of the CAPS IMS from 1 V less than or equal to E/Q less than 50 kV. Since our technique maps the observations into a local inertial frame, it does work during roll manoeuvres. We have made comparisons with Wilson et al. (2008) [2] (2005-358 and 2005-284) who performs a bi-Maxwellian fit to the ion singles data and our results are nearly identical. We will also make comparisons with results by Thomsen et al. (2010) [3]. Our analysis uses ion composition data to weight the non-compositional data, referred to as singles data, to separate H+, H2+ and water group ions (W+) from each other. The ion data set is especially valuable for measuring flow velocities for protons, which are more difficult to derive using singles data within the inner magnetosphere, where the signal is dominated by heavy ions (i.e., proton peak merges with W+ peak as low energy shoulder). Our technique uses a flux function, which is zero in the proper plasma flow frame, to estimate fluid parameter uncertainties. The comparisons investigate the experimental errors and potential for systematic errors in the analyses, including ours. The rolls provide the best data set when it comes to getting 4PI coverage of the plasma but are more susceptible to time aliasing effects. Since our analysis is a velocity moments technique it will work within the inner magnetosphere where pickup ions are important and velocity distributions are non-Maxwellian. So, we will present results inside Enceladus' L shell and determine if mass loading is important. In the future we plan to make comparisons with magnetic field observations, use Saturn ionosphere conductivities as

  6. Tethys and Dione as sources of outward-flowing plasma in Saturn's magnetosphere.

    PubMed

    Burch, J L; Goldstein, J; Lewis, W S; Young, D T; Coates, A J; Dougherty, M K; André, N

    2007-06-14

    Rotating at over twice the angular speed of Earth, Saturn imposes a rapid spin on its magnetosphere. As a result, cold, dense plasma is believed to be flung outward from the inner magnetosphere by centrifugal force and replaced by hotter, more tenuous plasma from the outer magnetosphere. The centrifugal interchange of plasmas in rotating magnetospheres was predicted many years ago and was conclusively demonstrated by observations in Jupiter's magnetosphere, which--like that of Saturn (but unlike that of Earth)--is rotationally dominated. Recent observations in Saturn's magnetosphere have revealed narrow injections of hot, tenuous plasma believed to be the inward-moving portion of the centrifugal interchange cycle. Here we report observations of the distribution of the angle between the electron velocity vector and the magnetic field vector ('pitch angle') obtained in the cold, dense plasma adjacent to these inward injection regions. The observed pitch-angle distributions are indicative of outward plasma flow and consistent with centrifugal interchange in Saturn's magnetosphere. Further, we conclude that the observed double-peaked ('butterfly') pitch-angle distributions result from the transport of plasma from regions near the orbits of Dione and Tethys, supporting the idea of distinct plasma tori associated with these moons.

  7. Plasma Entry from Tail into the Dipolar Magnetosphere During Substorms

    NASA Astrophysics Data System (ADS)

    Haerendel, Gerhard

    Plasma entering the dipolar magnetosphere from the tail has to overcome the obstacle presented by the conductivity enhancements caused by the poleward arc(s). While the arcs move poleward, the plasma proceeds equatorward as testified by the existence of a westward electric field. The arcs break into smaller-scale structures and loops with a tendency of eastward growth and expansion, although the basic driving force is directed earthward/equatorward. The likely reason is that the arc-related conductivity enhancements act as flow barriers and convert normal into shear stresses. The energy derived from the release of the shear stresses and dissipated in the arcs lowers the entropy content of the flux tubes and enables their earthward progression. In addition, poleward jumps of the breakup arcs are quite common. They result from refreshments of the generator plasma by the sequential arrival of flow bursts from the near-Earth neutral line. Once inside the oval, the plasma continues to move equatorward as manifested through north-south aligned auroral forms. Owing to the existence of an inner border of the oval, marked by the Region 2 currents, all flows are eventually diverted sunward.

  8. Magnetospheric plasma modeling (0-100 keV)

    NASA Technical Reports Server (NTRS)

    Garrett, H. B.; Spitale, G. C.

    1985-01-01

    Spacecraft surface charging, which is primarily a current balance phenomenon, is in general a function of the dominant currents to and from the vehicle's surface. Within the near-earth magnetosphere the dominant currents to the surface are the ambient space plasma fluxes between approximately 0 and 100 keV. A major effort to understand the near-earth environment was initiated when spacecraft charging became a major issue. The present paper has the objective to summarize the basic features of the models which have resulted from this effort. A description is given of four categories of models, based primarily on the degree of empirical and theoretical input. Types of quantitative models are discussed, taking into account definitions, statistical models, analytic models, static models, and time-dependent models. Engineering models are also considered, giving attention to baseline models and 'worst-case' models.

  9. Analysis of transfer processes through plasma boundaries of the magnetosphere

    NASA Astrophysics Data System (ADS)

    Kozak, Liudmyla; Savin, Sergey; Lui, Anthony Tat Yin; Prokhorenkov, Andrew

    Studying the fundamental properties of the interaction of the solar wind with the magnetosphere found superdiffusion processes in the boundary layers space plasma and 'distant' transfer mechanism (the influence of local microprocesses to global, and vice versa). Since the developed turbulence is characterized by a great number of degrees of freedom, nonlinearly interacting modes, multi-scale structure and random fluctuations of velocities so that the methods of statistical physics and theory of probability are most suitable for its description. In this study based on the mission Cluster measurements the characteristic turbulent regions in the boundary layers of Earth’s magnetosphere are being separated and the statistical characteristics are being obtained, which determine the transfer processes through plasma boundaries. Meanwhile, the set of different techniques was used which are based on the analysis of fluctuation distribution function and its moments. For the analysis of the turbulent processes we have carried out an investigation of structure functions for different orders and studied diffusion processes in different regions determined by a character of the dependence of the generalized diffusion coefficient on time. Basing on the results of studying structural functions of various orders, the conclusion is drawn that small scale turbulence in the foreshock, magnetosheath, turbulent boundary layer is described by different phenomenological models. Besides, we have obtained an increase of diffusion coefficient with time for the regions of magnetosheath. The work is done in the frame of complex program of NAS of Ukraine on space researches for 2012-1016, within the framework of the educational program No.2201250 “Education, Training of students, PhD students, scientific and pedagogical staff abroad” launched by the Ministry of Education and Science of Ukraine and under a partial support of the grant No. F 53.2/039.

  10. Plasma Distribution in Mercury's Magnetosphere Derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer Observations

    NASA Technical Reports Server (NTRS)

    Korth, Haje; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Solomon, Sean C.; McNutt, Ralph L.

    2014-01-01

    We assess the statistical spatial distribution of plasma in Mercury's magnetosphere from observations of magnetic pressure deficits and plasma characteristics by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. The statistical distributions of proton flux and pressure were derived from 10months of Fast Imaging Plasma Spectrometer (FIPS) observations obtained during the orbital phase of the MESSENGER mission. The Magnetometer-derived pressure distributions compare favorably with those deduced from the FIPS observations at locations where depressions in the magnetic field associated with the presence of enhanced plasma pressures are discernible in the Magnetometer data. The magnitudes of the magnetic pressure deficit and the plasma pressure agree on average, although the two measures of plasma pressure may deviate for individual events by as much as a factor of approximately 3. The FIPS distributions provide better statistics in regions where the plasma is more tenuous and reveal an enhanced plasma population near the magnetopause flanks resulting from direct entry of magnetosheath plasma into the low-latitude boundary layer of the magnetosphere. The plasma observations also exhibit a pronounced north-south asymmetry on the nightside, with markedly lower fluxes at low altitudes in the northern hemisphere than at higher altitudes in the south on the same field line. This asymmetry is consistent with particle loss to the southern hemisphere surface during bounce motion in Mercury's offset dipole magnetic field.

  11. Momentum transfer of solar wind plasma in a kinetic scale magnetosphere

    NASA Astrophysics Data System (ADS)

    Moritaka, Toseo; Kajimura, Yoshihiro; Usui, Hideyuki; Matsumoto, Masaharu; Matsui, Tatsuki; Shinohara, Iku

    2012-03-01

    Solar wind interaction with a kinetic scale magnetosphere and the resulting momentum transfer process are investigated by 2.5-dimensional full kinetic particle-in-cell simulations. The spatial scale of the considered magnetosphere is less than or comparable to the ion inertial length and is relevant for magnetized asteroids or spacecraft with mini-magnetosphere plasma propulsion. Momentum transfer is evaluated by studying the Lorentz force between solar wind plasma and a hypothetical coil current density that creates the magnetosphere. In the zero interplanetary magnetic field (IMF) limit, solar wind interaction goes into a steady state with constant Lorentz force. The dominant Lorentz force acting on the coil current density is applied by the thin electron current layer at the wind-filled front of the magnetosphere. Dynamic pressure of the solar wind balances the magnetic pressure in this region via electrostatic deceleration of ions. The resulting Lorentz force is characterized as a function of the scale of magnetosphere normalized by the electron gyration radius, which determines the local structure of the current layer. For the finite northward IMF case, solar wind electrons flow into the magnetosphere through the reconnecting region. The inner electrons enhance the ion deceleration, and this results in temporal increment of the Lorentz force. It is concluded that the momentum transfer of solar wind plasma could take place actively with variety of kinetic plasma phenomena, even in a magnetosphere with a small scale of less than the ion inertial length.

  12. Transport and acceleration of plasma in the magnetospheres of Earth and Jupiter and expectations for Saturn

    NASA Astrophysics Data System (ADS)

    Kivelson, M. G.

    The first comparative magnetospheres conference was held in Frascati, Italy thirty years ago this summer, less than half a year after the first spacecraft encounter with Jupiter's magnetosphere (Formisano, V. (Ed.), The Magnetospheres of the Earth and Jupiter, Proceedings of the Neil Brice Memorial Symposium held in Frascati, Italy, May 28-June 1, 1974. D. Reidel Publishing Co., Boston, USA, 1975). Disputes highlighted various issues still being investigated, such as how plasma transport at Jupiter deviates from the prototypical form of transport at Earth and the role of substorms in Jupiter's dynamics. Today there is a wealth of data on which to base the analysis, data gathered by seven missions that culminated with Galileo's 8-year orbital tour. We are still debating how magnetic flux is returned to the inner magnetosphere following its outward transport by iogenic plasma. We are still uncertain about the nature of sporadic dynamical disturbances at Jupiter and their relation to terrestrial substorms. At Saturn, the centrifugal stresses are not effective in distorting the magnetic field, so in some ways the magnetosphere appears Earthlike. Yet the presence of plasma sources in the close-in equatorial magnetosphere parallels conditions at Jupiter. This suggests that we need to study both Jupiter and Earth when thinking about what to anticipate from Cassini's exploration of Saturn's magnetosphere. This paper addresses issues relevant to plasma transport and acceleration in all three magnetospheres.

  13. Magnetosphere-ionosphere coupling and scale breaking of a plasma cloud in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Haerendel, Gerhard; Mende, Stephen B.

    2012-09-01

    The goal of this paper is to deliver a long-missing interpretation of a central issue of the NASA-MPE barium injection experiment performed in September 1971. It pertains to the interaction with the ionosphere. Observations of the cloud's motion revealed no obvious sign of such interaction. The barium vapor was released from a Scout rocket at an altitude of 31,000 km above South America during late evening hours and was observed for more than 4000 s. The barium plasma split into several field-parallel streaks which moved for a long time as if subject to constant acceleration as viewed from the inertial frame of the rocket at release. This means that no reflection of energy due to a mismatch of ionospheric conductivity and the characteristic impedance of an impinging Alfvén wave was observed. It is this finding that has never been properly interpreted. Furthermore, after a careful assessment of the barium cloud properties and environmental parameters, we find a theoretical coupling time to the ambient flow which turns out to be substantially longer than observed. Although this appears to indicate that some interaction with the ionosphere occurred, we can rule out multiple wave reflections during the observed acceleration phase. Discarding other possibilities, we interpret the observed motions as sign of perfect matching of the momentum and energy flux into the ionosphere with the rate of dissipation. This is achieved during the initial phase by scale breaking of the cloud into streaks with narrow widths which allow parallel potential drops along the Alfvén wings because of the waves' inertial nature and inside the lower ionosphere owing to the finite parallel resistivity, thereby greatly reducing the effective Pedersen conductivity. The significance of this finding goes beyond understanding the barium injection experiment. It sheds light on how magnetospheric plasma irregularities can share momentum and energy with the ionosphere in an optimized fashion.

  14. MESSENGER observations of the plasma depletion layer in Mercury's magnetosphere

    NASA Astrophysics Data System (ADS)

    Gershman, D. J.; Slavin, J. A.; Raines, J. M.; Zurbuchen, T.; Anderson, B. J.; Korth, H.; Baker, D. N.; Solomon, S. C.

    2012-12-01

    Measurements made with the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft's Fast Imaging Plasma Spectrometer (FIPS) and Magnetometer (MAG) are used to determine the properties of the plasma depletion layer (PDL) that is found just exterior to Mercury's dayside magnetopause. PDLs form when interplanetary magnetic flux tubes drape around and are compressed against an obstacle to the solar wind. Such obstacles include not only planetary magnetic fields such as that of Mercury, but also the ionospheres of comets and planets without internal fields such as Venus. It is this compression of the draped flux tubes against the magnetopause that causes the solar wind plasma to flow away from the subsolar region and deplete the flux tubes of plasma. Observations of the PDL at Earth have shown that such properties of this layer as its thickness and its reduction in density are strong functions of the solar wind Alfvénic Mach number and the orientation of the interplanetary magnetic field (IMF). The MESSENGER measurements show that a PDL is indeed present at Mercury and confirm the theoretical prediction that the thickness and degree of depletion is enhanced for the very low Alfvénic Mach numbers in the inner Solar System, on average a factor of ~2 smaller than those at Earth. For several transits of the spacecraft through the magnetosheath near local noon, each lasting only a few minutes, the plasma and magnetic field of the PDL have been sampled, capturing a snapshot of the shocked solar wind near the stagnation point. The relative density reduction and thickness of the PDL are examined for each magnetospheric pass and placed into context with the set of available solar wind forcing conditions and IMF orientations in order to study the formation of these layers at Mercury with and without the presence of dayside magnetic reconnection.

  15. Survey of low energy plasma electrons in Saturn's magnetosphere: Voyagers 1 and 2

    NASA Technical Reports Server (NTRS)

    Sittler, E. C., Jr.; Ogilvie, K. W.; Scudder, J. D.

    1983-01-01

    The low energy plasma electron environment within Saturn's magnetosphere was surveyed by the Plasma Science Experiment (PLS) during the Voyager encounters with Saturn. Over the full energy range of the PLS instrument (10 eV to 6 keV) the electron distribution functions are clearly non-Maxwellian in character; they are composed of a cold (thermal) component with Maxwellian shape and a hot (suprathermal) non-Maxwellian component. A large scale positive radial gradient in electron temperature is observed, increasing from less than 1 eV in the inner magnetosphere to as high as 800 eV in the outer magnetosphere. Three fundamentally different plasma regimes were identified from the measurements: (1) the hot outer magnetosphere, (2) the extended plasma sheet, and (3) the inner plasma torus.

  16. Penetration of magnetosheath plasma into dayside magnetosphere: 1. Density, velocity, and rotation

    NASA Astrophysics Data System (ADS)

    Lyatsky, Wladislaw; Pollock, Craig; Goldstein, Melvyn L.; Lyatskaya, Sonya; Avanov, Levon

    2016-08-01

    In this study, we examine a large number of plasma structures (filaments), observed with the Cluster spacecraft during 2 years (2007-2008) in the dayside magnetosphere but consisting of magnetosheath plasma. To reduce the effects observed in the cusp regions and on magnetosphere flanks, we consider these events predominantly inside the narrow cone ≤30° about the subsolar point. Two important features of these filaments are (i) their stable antisunward (earthward) motion inside the magnetosphere, whereas the ambient magnetospheric plasma moves usually in the opposite direction (sunward), and (ii) between these filaments and the magnetopause, there is a region of magnetospheric plasma, which separates these filaments from the magnetosheath. The stable earthward motion of these filaments and the presence of a region of magnetospheric plasma between these filaments and the magnetopause show the possible disconnection of these filaments from the magnetosheath, as suggested earlier by many researchers. The results also show that these events cannot be a result of back-and-forth motions of magnetopause position or surface waves propagating on the magnetopause. Another important feature of these filaments is their rotation about the filament axis, which might be a result of their passage through the velocity shear on magnetopause boundary. After crossing the velocity shear, the filaments get a rotational velocity, which has opposite directions in the noon-dusk and noon-dawn sectors. This rotation velocity may be an important factor, supporting the stability of these filaments and providing their motion into the magnetosphere.

  17. Differential drift of plasma clouds in the magnetosphere: an update

    NASA Astrophysics Data System (ADS)

    Lemaire, J. F.

    2001-07-01

    First, Brice's (Journal of Geophysical Research 72 (1967) 5193) original theory for the formation of the plasmapause is recalled. Next, the motivation for writing a modification to this early theory is pointed out. The key aspects of Brice's manuscript are outlined and discussed. The mechanism of interchange driven by gravitational forces, centrifugal effects and kinetic pressure is considered in the cases when the integrated Pedersen conductivity is (i) negligibly small (as in Chandrasekhar's, Plasma Physics, University of Chicago Press, Chicago, 1960, 217 pp. and Longmire's, Elementary Plasma Physics, Wiley Interscience, New York, 1963, 296 pp., textbooks), (ii) infinitely large (as in many magnetospheric convection models), or (iii) has a finite value of the order of 0.2 mho, as in the Earth's ionosphere. Updates of this theory of interchange resulting from the existence of weak double layers, from quasi-interchange, or from the effects of an additional population of energetic ring-current particles forming the extended tail of the velocity distribution function, have also been reexamined.

  18. Magnetic field fluctuations in Saturn's magnetosphere: A new laboratory of plasma turbulence with important implications for the magnetospheric energy budget

    NASA Astrophysics Data System (ADS)

    von Papen, M.; Saur, J.; Alexandrova, O.

    2013-12-01

    We analyze the statistical properties of magnetic field fluctuations measured by the Cassini spacecraft inside Saturn's plasma sheet. We introduce Saturn's magnetosphere as a new laboratory for plasma turbulence, where the background magnetic field is strong (B0≤75nT) and the ion plasma βi=0.04-1 is low. We also show that the dissipation of these magnetic field fluctuations might play a crucial role for the energy budget of the magnetospheric plasma. In a case study of the second orbit of Cassini around Saturn we show that the power spectral densities of the fluctuations have a variable low frequency spectral range and a continously present power law in the high frequency range, which shows characteristics of a turbulent cascade. A spectral break that correlates with water group ion scales seperates the two frequency ranges. We carry out a statistical study of the high frequency fluctuations and find an average spectral slope of -2.6. The probability density functions of the fluctuations have increasingly non-gaussian tails with frequency resulting in a power law increase of the kurtosis, which indicates intermittency and a multifractal nature of the fluctuations. We estimate the energy flux, that is contained in the turbulent cascade as 30-50GW, which is on the same order of magnitude as needed to heat an adiabatically expanding plasma to the temperatures measured in Saturn's magnetosphere. We compare these results with heating rates estimated for Jupiter's magnetosphere. Superposition of 1136 PSD of 10min time series as function of k⊥ρW (gyro radius of water group ions). Histogram of spectral indices for k⊥ρW>2.

  19. PC-5 Waves and Low Energy Plasma in the Outer Magnetosphere

    NASA Technical Reports Server (NTRS)

    Gallanger, Dennis L.; Vaisberg, Oleg L.; Coffey, Victoria N.

    1999-01-01

    The Interball Tail Probe crosses the dayside magnetopause at low latitudes where it frequently measures low energy ion plasma (<100 eV) in the outer magnetosphere. We present the wave characteristics associated with this cold component.

  20. Los Alamos NEP research in advanced plasma thrusters

    NASA Technical Reports Server (NTRS)

    Schoenberg, Kurt; Gerwin, Richard

    1991-01-01

    Research was initiated in advanced plasma thrusters that capitalizes on lab capabilities in plasma science and technology. The goal of the program was to examine the scaling issues of magnetoplasmadynamic (MPD) thruster performance in support of NASA's MPD thruster development program. The objective was to address multi-megawatt, large scale, quasi-steady state MPD thruster performance. Results to date include a new quasi-steady state operating regime which was obtained at space exploration initiative relevant power levels, that enables direct coaxial gun-MPD comparisons of thruster physics and performance. The radiative losses are neglible. Operation with an applied axial magnetic field shows the same operational stability and exhaust plume uniformity benefits seen in MPD thrusters. Observed gun impedance is in close agreement with the magnetic Bernoulli model predictions. Spatial and temporal measurements of magnetic field, electric field, plasma density, electron temperature, and ion/neutral energy distribution are underway. Model applications to advanced mission logistics are also underway.

  1. Plasma distribution in Mercury's magnetosphere inferred from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer observations

    NASA Astrophysics Data System (ADS)

    Korth, H.; Anderson, B. J.; Raines, J. M.; Gershman, D. J.; Slavin, J. A.; Zurbuchen, T.; Solomon, S. C.; McNutt, R. L., Jr.

    2013-12-01

    We present average plasma distributions in Mercury's magnetosphere inferred independently from magnetic field and plasma measurements by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Plasma distributions were derived from magnetic pressure deficits measured during the first 10 months of MESSENGER orbital operations under the assumption of constant total pressure. Statistical distributions of proton flux and pressure were also derived from Fast Imaging Plasma Spectrometer (FIPS) observations during the same period. The pressures inferred from magnetic pressure deficits and the plasma data agree on average, although they differ by a factor of ~2 for individual events. The spatial distributions of magnetic pressure deficits derived from Magnetometer observations compare favorably with the distribution of proton pressure deduced from the FIPS observations. The FIPS distributions provide better statistics than the magnetic depression data in regions where the plasma is more tenuous and magnetic pressure deficits are difficult to identify definitively. The plasma data reveal features not previously identified in the Magnetometer data, such as an enhanced plasma population near the magnetopause flanks indicating entry of magnetosheath plasma into the low-latitude boundary layer of the magnetosphere. On nightside closed field lines, plasma pressures in the south are much greater than they are in the north. Locations of low plasma pressure in the north correspond to sample altitudes that map to southern conjugate locations below the planetary surface. The asymmetry is attributed to particle loss to the southern hemisphere surface during bounce motion in Mercury's magnetic field. The plasma observations confirm the northward offset in the planetary dipole.

  2. Los Alamos research in nozzle based coaxial plasma thrusters

    NASA Technical Reports Server (NTRS)

    Scheuer, Jay; Schoenberg, Kurt; Gerwin, Richard; Henins, Ivars; Moses, Ronald, Jr.; Wurden, Glen

    1992-01-01

    The topics are presented in viewgraph form and include the following: research approach; perspectives on efficient magnetoplasmadynamic (MPD) operation; NASA and DOE supported research in ideal magnetohydrodynamic plasma acceleration and flow, electrode phenomena, and magnetic nozzles; and future research directions and plans.

  3. The role of plasma/neutral source and loss processes in shaping the giant planet magnetospheres

    NASA Astrophysics Data System (ADS)

    Delamere, P. A.

    2014-12-01

    The giant planet magnetospheres are filled with neutral and ionized gases originating from satellites orbiting deep within the magnetosphere. The complex chemical and physical pathways for the flow of mass and energy in this partially ionized plasma environment is critical for understanding magnetospheric dynamics. The flow of mass at Jupiter and Saturn begins, primarily, with neutral gases emanating from Io (~1000 kg/s) and Enceladus (~200 kg/s). In addition to ionization losses, the neutral gases are absorbed by the planet, its rings, or escape at high speeds from the magnetosphere via charge exchange reactions. The net result is a centrifugally confined torus of plasma that is transported radially outward, distorting the magnetic field into a magnetodisc configuration. Ultimately the plasma is lost to the solar wind. A critical parameter for shaping the magnetodisc and determining its dynamics is the radial plasma mass transport rate (~500 kg/s and ~50 kg/s for Jupiter and Saturn respectively). Given the plasma transport rates, several simple properties of the giant magnetodiscs can be estimated including the physical scale of the magnetosphere, the magnetic flux transport, and the magnitude of azimuthal magnetic field bendback. We will discuss transport-related magnetic flux conservation and the mystery of plasma heating—two critical issues for shaping the giant planet magnetospheres.

  4. Self-Consistent Magnetosphere-Ionosphere Coupling and Associated Plasma Energization Processes

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Magnetosphere-Ionosphere (MI) coupling and associated with this process electron and ion energization processes have interested scientists for decades and, in spite of experimental and theoretical research efforts, are still ones of the least well known dynamic processes in space plasma physics. The reason for this is that the numerous physical processes associated with MI coupling occur over multiple spatial lengths and temporal scales. One typical example of MI coupling is large scale ring current (RC) electrodynamic coupling that includes calculation of the magnetospheric electric field that is consistent with the ring current (RC) distribution. A general scheme for numerical simulation of such large-scale magnetosphere-ionosphere coupling processes has been presented earlier in many works. The mathematical formulation of these models are based on "modified frozen-in flux theorem" for an ensemble of adiabatically drifting particles in the magnetosphere. By tracking the flow of particles through the inner magnetosphere, the bounce-averaged phase space density of the hot ions and electrons can be reconstructed and the magnetospheric electric field can be calculated such that it is consistent with the particle distribution in the magnetosphere. The new a self-consistent ring current model has been developed that couples electron and ion magnetospheric dynamics with calculation of electric field. Two new features were taken into account in addition to the RC ions, we solve an electron kinetic equation in our model, self-consistently including these results in the solution. Second, using different analytical relationships, we calculate the height integrated ionospheric conductances as the function of precipitated high energy magnetospheric electrons and ions as produced by our model. This results in fundamental changes to the electric potential pattern in the inner magnetosphere, with a smaller Alfven boundary than previous potential formulations would predict but

  5. Hot Plasma Composition Analyzer for the Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Young, D. T.; Burch, J. L.; Gomez, R. G.; De Los Santos, A.; Miller, G. P.; Wilson, P.; Paschalidis, N.; Fuselier, S. A.; Pickens, K.; Hertzberg, E.; Pollock, C. J.; Scherrer, J.; Wood, P. B.; Donald, E. T.; Aaron, D.; Furman, J.; George, D.; Gurnee, R. S.; Hourani, R. S.; Jacques, A.; Johnson, T.; Orr, T.; Pan, K. S.; Persyn, S.; Pope, S.; Roberts, J.; Stokes, M. R.; Trattner, K. J.; Webster, J. M.

    2016-03-01

    This paper describes the science motivation, measurement objectives, performance requirements, detailed design, approach and implementation, and calibration of the four Hot Plasma Composition Analyzers (HPCA) for the Magnetospheric Multiscale mission. The HPCA is based entirely on electrostatic optics combining an electrostatic energy analyzer with a carbon-foil based time-of-flight analyzer. In order to fulfill mission requirements, the HPCA incorporates three unique technologies that give it very wide dynamic range capabilities essential to measuring minor ion species in the presence of extremely high proton fluxes found in the region of magnetopause reconnection. Dynamic range is controlled primarily by a novel radio frequency system analogous to an RF mass spectrometer. The RF, in combination with capabilities for high TOF event processing rates and high current micro-channel plates, ensures the dynamic range and sensitivity needed for accurate measurements of ion fluxes between ˜1 eV and 40 keV that are expected in the region of reconnection events. A third technology enhances mass resolution in the presence of high proton flux.

  6. Hot Plasma and Energetic Particles in Neptune's Magnetosphere.

    PubMed

    Krimigis, S M; Armstrong, T P; Axford, W I; Bostrom, C O; Cheng, A F; Gloeckler, G; Hamilton, D C; Keath, E P; Lanzerotti, L J; Mauk, B H; Van Allen, J A

    1989-12-15

    The low-energy charged particle (LECP) instrument on Voyager 2 measured within the magnetosphere of Neptune energetic electrons (22 kiloelectron volts /=0.5 MeV per nucleon) energies, using an array of solid-state detectors in various configurations. The results obtained so far may be summarized as follows: (i) A variety of intensity, spectral, and anisotropy features suggest that the satellite Triton is important in controlling the outer regions of the Neptunian magnetosphere. These features include the absence of higher energy (>/=150 keV) ions or electrons outside 14.4 R(N) (where R(N) = radius of Neptune), a relative peak in the spectral index of low-energy electrons at Triton's radial distance, and a change of the proton spectrum from a power law with gamma >/= 3.8 outside, to a hot Maxwellian (kT [unknown] 55 keV) inside the satellite's orbit. (ii) Intensities decrease sharply at all energies near the time of closest approach, the decreases being most extended in time at the highest energies, reminiscent of a spacecraft's traversal of Earth's polar regions at low altitudes; simultaneously, several spikes of spectrally soft electrons and protons were seen (power input approximately 5 x 10(-4) ergs cm(-2) s(-1)) suggestive of auroral processes at Neptune. (iii) Composition measurements revealed the presence of H, H(2), and He(4), with relative abundances of 1300:1:0.1, suggesting a Neptunian ionospheric source for the trapped particle population. (iv) Plasma pressures at E >/= 28 keV are maximum at the magnetic equator with beta approximately 0.2, suggestive of a relatively empty magnetosphere, similar to that of Uranus. (v) A potential signature of satellite 1989N1 was seen, both inbound and outbound; other possible signatures of the moons and rings are evident in the data but cannot be positively identified in the

  7. Some sources of plasma inhomogeneities in the solar wind in front of the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Grib, S. A.; Pushkar, E. A.; Leora, S. N.

    2016-12-01

    The origination of various plasma inhomogeneities in the magnetosheath in front of the Earth's magnetosphere is analyzed within classical magnetohydrodynamics. The effect of directional discontinuities or tangential and rotational discontinuities of the solar wind on plasma is studied. The origination of inhomogeneities of the type of secondary MHD waves in the magnetosheath is shown; the former equalize plasma parameters when restoring the stationary state. The effect of a rotational discontinuity on the bow shock-Earth's magnetosphere system is of special interest, with distinguishing of plasma inhomogeneities of the plateau type observed in the near-Earth space.

  8. Research on fission induced plasmas and nuclear pumped lasers at the Los Alamos Scientific Laboratory

    NASA Technical Reports Server (NTRS)

    Helmick, H. H.

    1979-01-01

    A program of research on gaseous uranium and uranium plasmas is being conducted at The Los Alamos Scientific Laboratory under sponsorship of the National Aeronautics and Space Administration. The objective of this work is twofold: (1) to demonstrate the proof of principle of a gaseous uranium fueled reactor, and (2) pursue fundamental research on nuclear pumped lasers. The relevancy of the two parallel programs is embodied in the possibility of a high-performance uranium plasma reactor being used as the power supply for a nuclear pumped laser system. The accomplishments in the two above fields are summarized

  9. Penetration of Magnetosheath Plasma into Dayside Magnetosphere: 1. Density, Velocity, and Rotation

    NASA Technical Reports Server (NTRS)

    Lyatsky, Wladislaw; Pollock, Craig; Goldstein, Melvyn L.; Lyatsky, Sonya; Avanov, Levon Albert

    2016-01-01

    In this study, we examine a large number of plasma structures (filaments), observed with the Cluster spacecraft during 2 years (2007-2008) in the dayside magnetosphere but consisting of magnetosheath plasma. To reduce the effects observed in the cusp regions and on magnetosphere flanks, we consider these events predominantly inside the narrow cone less than 30 about the subsolar point. Two important features of these filaments are (i) their stable antisunward (earthward) motion inside the magnetosphere, whereas the ambient magnetospheric plasma moves usually in the opposite direction (sunward), and (ii) between these filaments and the magnetopause, there is a region of magnetospheric plasma, which separates these filaments from the magnetosheath. The stable earthward motion of these magnetopause show the possible disconnection of these filaments from the magnetosheath, as suggested earlier by many researchers. The results also show that these events cannot be a result of back-and-forth motions of magnetopause position or surface waves propagating on the magnetopause. Another important feature of these filaments is their rotation about the filament axis, which might be a result of their passage through the velocity shear on magnetopause boundary. After crossing the velocity shear, the filaments get a rotational velocity, which has opposite directions in the noon-dusk and noon-dawn sectors. This rotation velocity may be an important factor, supporting the stability of these filaments and providing their motion into the magnetosphere.

  10. Study of plasma pressure distribution in the inner magnetosphere using the low-altitude satellite data as one of important elements of the magnetospheric dynamics

    NASA Astrophysics Data System (ADS)

    Stepanova, M.; Antonova, E. E.; Bosqued, J. M.

    Plasma pressure distribution in the inner magnetosphere is one of the key parameters for understanding the main magnetospheric processes including geomagnetic storms and substorms Therefore during the last decades many efforts were concentrated on the study of pressure distribution in the inner magnetosphere However the pressure profiles obtained from in-situ particle measurements by the high-altitude satellites inside the plasma sheet and other regions of the magnetosphere do not allow the tracking the pressure variations related to the magnetospheric dynamics because a time interval neaded to do this generally exceeds the characteristic times of the main magnetospheric processes On contrary fast movement of low-altitude satellites makes it possible to catch quasi-instantaneous radial or azimuthal profiles of plasma pressure along the satellite trayectory using the precipitating particle flux data in the regions of isotropic plasma pressure The low-altitude polar-orbiting Aureol-3 satellite was used for this study IGRF Tsyganenko 2001 and Tsyganenko 2004 storm time geomagnetic field models were used for the pressure mapping into the equatorial plane and also to evaluate the corresponding volume of the magnetic flux tube and the magnetic pressure Study of azumuthal plasma pressure gradients showed that these gradients can be a source of the Iijima and Potemra s field-aligned current system Study of radial plasma gradients showed that during quiet geomagnetic condition the profiles obtained coincide with the results obtained previously from the high-altitude

  11. Convection of Plasmaspheric Plasma into the Outer Magnetosphere and Boundary Layer Region: Initial Results

    NASA Technical Reports Server (NTRS)

    Ober, Daniel M.; Horwitz, J. L.

    1998-01-01

    We present initial results on the modeling of the circulation of plasmaspheric-origin plasma into the outer magnetosphere and low-latitude boundary layer (LLBL), using a dynamic global core plasma model (DGCPM). The DGCPM includes the influences of spatially and temporally varying convection and refilling processes to calculate the equatorial core plasma density distribution throughout the magnetosphere. We have developed an initial description of the electric and magnetic field structures in the outer magnetosphere region. The purpose of this paper is to examine both the losses of plasmaspheric-origin plasma into the magnetopause boundary layer and the convection of this plasma that remains trapped on closed magnetic field lines. For the LLBL electric and magnetic structures we have adopted here, the plasmaspheric plasma reaching the outer magnetosphere is diverted anti-sunward primarily along the dusk flank. These plasmas reach X= -15 R(sub E) in the LLBL approximately 3.2 hours after the initial enhancement of convection and continues to populate the LLBL for 12 hours as the convection electric field diminishes.

  12. Convection of Plasmaspheric Plasma into the Outer Magnetosphere and Boundary Layer Region: Initial Results

    NASA Technical Reports Server (NTRS)

    Ober, Daniel M.; Horwitz, J. L.; Gallagher, D. L.

    1998-01-01

    We present initial results on the modeling of the circulation of plasmaspheric- origin plasma into the outer magnetosphere and low-latitude boundary layer (LLBL), using a dynamic global core plasma model (DGCPM). The DGCPM includes the influences of spatially and temporally varying convection and refilling processes to calculate the equatorial core plasma density distribution throughout the magnetosphere. We have developed an initial description of the electric and magnetic field structures in the outer magnetosphere region. The purpose of this paper is to examine both the losses of plasmaspheric-origin plasma into the magnetopause boundary layer and the convection of this plasma that remains trapped on closed magnetic field lines. For the LLBL electric and magnetic structures we have adopted here, the plasmaspheric plasma reaching the outer magnetosphere is diverted anti-sunward primarily along the dusk flank. These plasmas reach X = -15 R(sub E) in the LLBL approximately 3.2 hours after the initial enhancement of convection and continues to populate the LLBL for 12 hours as the convection electric field diminishes.

  13. Plasma dynamics in Saturn's middle-latitude ionosphere and implications for magnetosphere-ionosphere coupling

    NASA Astrophysics Data System (ADS)

    Sakai, Shotaro; Watanabe, Shigeto

    2016-08-01

    A multifluid model is used to investigate how Saturn's magnetosphere affects ionosphere. The model includes a magnetospheric plasma temperature of 2 eV as a boundary condition. The main results are: (1) H+ ions are accelerated along magnetic field lines by ambipolar electric fields and centrifugal force, and have an upward velocity of about 10 km/s at 8000 km; (2) the ionospheric plasma temperature is 10,000 K at 5000 km, and is significantly affected by magnetospheric heat flow at high altitudes; (3) modeled electron densities agree with densities from occultation observations if the maximum neutral temperature at a latitude of 54˚ is about 900 K or if electrons are heated near an altitude of 2500 km; (4) electron heating rates from photoelectrons (≈100 K/s) can also give agreement with observed electron densities when the maximum neutral temperature is lower than 700 K (note that Cassini observations give 520 K); and (5) the ion temperature is high at altitudes above 4000 km and is almost the same as the electron temperature. The ionospheric height-integrated Pedersen conductivity, which affects the magnetospheric plasma velocity, varies with local time with values between 0.4 and 10 S. We suggest that the sub-corotating ion velocity in the inner magnetosphere depends on the local time, because the conductivity generated by dust-plasma interactions in the inner magnetosphere is almost comparable to the ionospheric conductivity. This indicates that magnetosphere-ionosphere coupling is highly important in the Saturn system.

  14. Magnetic and plasma response of the Earth's magnetosphere to interplanetary shock

    NASA Astrophysics Data System (ADS)

    Du, A.; Cao, X.; Wang, R.; Zhang, Y.

    2013-12-01

    In this paper, we investigate the global response of magnetosphere to interplanetary shock, and focus on the magnetic and plasma variations related to aurora. The analysis utilizes data from simultaneous observations of interplanetary shocks from available spacecraft in the solar wind and the Earth's magnetosphere such as ACE, Wind and SOHO in solar wind, LANL and GOES in outer magnetosphere, TC1 in the midinight neutral plasma sheet, Geotail and Polar in dusk side of plasma sheet, and Cluster in downside LLBL. The shock front speed is ~1051 km/s in the solar wind, and ~981km/s in the Earth's magnetosphere. The shock is propagating anti-sunward (toward the Earth) in the plasma frame with a speed of ~320 km/s. After the shock bumps at the magnetopause, the dayside aurora brightens, then nightside aurora brightens and expanses to poleward. During the aurora activity period, the fast earthward and tailward flows in plasma sheet are observed by TC1 (X~7.1 Re, Y~1.2 Re). The variation of magnetic field and plasma in duskside of magnetosphere is weaker than that in dawnside. At low latitude boundary layer (LLBL), the Cluster spacecraft detected rolled-up large scale vortices generated by the Kelvin-Helmholtz instability (KHI). Toroidal oscillations of the magnetic field in the LLBL might be driven by the Kelvin-Helmholtz instability. The strong IP shock highly compresses the magnetopause and the outer magnetosphere. This process may also lead to particle precipitation and auroral brightening (Zhou and Tsurutani, 1999; Tsurutani et al., 2001 and 2003).

  15. Yosemite Conference on Ionospheric Plasma in the Magnetosphere: Sources, Mechanisms and Consequences, meeting report

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Burch, J. L.; Klumpar, D. M.; Moore, T. E.; Waite, J. H., Jr.

    1987-01-01

    The sixth biennial Yosemite topical conference and the first as a Chapman Conference was held on February 3 to 6, 1986. Due to the recent changes in our perception of the dynamics of the ionospheric/magnetospheric system, it was deemed timely to bring researchers together to discuss and contrast the relative importance of solar versus terrestrial sources of magnetospheric plasma. Although the solar wind was once thought to dominate the supply of plasma in the Earth's magnetosphere, it is now thought that the Earth's ionosphere is a significant contributor. Polar wind and other large volume outflows of plasma have been seen at relatively high altitudes over the polar cap and are now being correlated with outflows found in the magnetotail. The auroral ion fountain and cleft ion fountain are examples of ionospheric sources of plasma in the magnetosphere, observed by the Dynamics Explorer 1 (DE 1) spacecraft. The conference was organized into six sessions: four consisting of prepared oral presentations, one poster session, and one session for open forum discussion. The first three oral sessions dealt separately with the three major topics of the conference, i.e., the sources, mechanisms, and consequences of ionospheric plasma in the magnetosphere. A special session of invited oral presentations was held to discuss extraterrestrial ionospheric/magnetospheric plasma processes. The poster session was extended over two evenings during which presenters discussed their papers on a one-on-one basis. The last session of the conferences was reserved for open discussions of those topics or ideas considered most interesting or controversial.

  16. Plasma Density and Radio Echoes in the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Calvert, W.

    1995-01-01

    This project provided a opportunity to study a variety of interesting topics related to radio sounding in the magnetosphere. The results of this study are reported in two papers which have been submitted for publication in the Journal of Geophysical Research and Radio Science, and various aspects of this study were also reported at meetings of the American Geophysical Union (AGU) at Baltimore, Maryland and the International Scientific Radio Union (URSI) at Boulder, Colorado. The major results of this study were also summarized during a one-day symposium on this topic sponsored by Marshall Space Flight Center in December 1994. The purpose of the study was to examine the density structure of the plasmasphere and determine the relevant mechanisms for producing radio echoes which can be detected by a radio sounder in the magnetosphere. Under this study we have examined density irregularities, biteouts, and outliers of the plasmasphere, studied focusing, specular reflection, ducting, and scattering by the density structures expected to occur in the magnetosphere, and predicted the echoes which can be detected by a magnetospheric radio sounder.

  17. Linking Plasma Conditions in the Magnetosphere with Ionospheric Signatures

    NASA Technical Reports Server (NTRS)

    Rastaetter, Lutz; Kozyra, Janet; Kuznetsova, Maria M.; Berrios, David H.

    2012-01-01

    Modeling of the full magnetosphere, ring current and ionosphere system has become an indispensable tool in analyzing the series of events that occur during geomagnetic storms. The CCMC has a full model suite available for the magnetosphere, together with visualization tools that allow a user to perform a large variety of analyses. The January, 21, 2005 storm was a moderate-size storm that has been found to feature a large penetration electric field and unusually large polar caps (low-latitude precipitation patterns) that are otherwise found in super storms. Based on simulations runs at CCMC we can outline the likely causes of this behavior. Using visualization tools available to the online user we compare results from different magnetosphere models and present connections found between features in the magnetosphere and the ionosphere that are connected magnetically. The range of magnetic mappings found with different models can be compared with statistical models (Tsyganenko) and the model's fidelity can be verified with observations from low earth orbiting satellites such as DMSP and TIMED.

  18. Plasma depletions in the Jovian magnetosphere - Evidence of transport and solar wind interaction

    NASA Technical Reports Server (NTRS)

    Mcnutt, Ralph L., Jr.; Coppi, Paolo S.; Selesnick, Richard S.; Coppi, Bruno

    1987-01-01

    A series of plasma voids ('dropouts') was observed by the Plasma Science (PLS) experiment in Jupiter's magnetosphere during the Voyager 2 encounter with that planet. A reexamination of Voyager 2 data has led to the conclusion that the dropout phenomenon cannot be a manifestation of a plasma wake produced by Ganymede. Rather, the appearance of the dropouts is attributed to changes in the upstream solar wind conditions and the global state of the magnetosphere; the proximity of Voyager 2 to Ganymede at the time is considered to be coincidental. It is suggested that these dropouts are evidence of a state of 'bubbling' of the magnetosphere that alternates with 'laminar' states in which, as in the case of the Voyager 1 encounter with Jupiter, voids are not present and that these states correspond to different processes by which plasma is transported out of the system. The nature of these states is related to changes in the magnitude of the upstream solar wind ram pressure. In the bubbling state, this pressure is higher than in the laminar state and drives an intermittent instability. The analysis presented is one of the first attempts to introduce, in space physics, recently acquired theoretical notions of the physics of the finite-beta plasmas of which the Jovian magnetospheric plasma is an important example.

  19. A Study of Ion Outflow as a Source of Plasma for the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Chappell, Charles R.

    2003-01-01

    Spacecraft measurements beginning in the early 1970 s gave indications that the ionosphere was a contributor to the energetic particle population of the Earth s magnetosphere This surprising result ran counter to the previously accepted model that the magnetospheric plasmas, because of their higher energies, must have come from the solar wind. Indeed, the original discovery of the Van Allen radiation belts, with energies of millions of electron volts, set a strong community belief in the sun as the plasma source because of the dramatic difference in the radiation belt energy and that of the Earth s ionospheric source.

  20. Plasma Composition in Jupiter's Magnetosphere: Initial Results from the Solar Wind Ion Composition Spectrometer.

    PubMed

    Geiss, J; Gloeckler, G; Balsiger, H; Fisk, L A; Galvin, A B; Gliem, F; Hamilton, D C; Ipavich, F M; Livi, S; Mall, U; Ogilvie, K W; von Steiger, R; Wilken, B

    1992-09-11

    The ion composition in the Jovian environment was investigated with the Solar Wind Ion Composition Spectrometer on board Ulysses. A hot tenuous plasma was observed throughout the outer and middle magnetosphere. In some regions two thermally different components were identified. Oxygen and sulfur ions with several different charge states, from the volcanic satellite lo, make the largest contribution to the mass density of the hot plasma, even at high latitude. Solar wind particles were observed in all regions investigated. Ions from Jupiter's ionosphere were abundant in the middle magnetosphere, particularly in the highlatitude region on the dusk side, which was traversed for the first time.

  1. Plasma composition in Jupiter's magnetosphere - Initial results from the Solar Wind Ion Composition Spectrometer

    NASA Technical Reports Server (NTRS)

    Geiss, J.; Gloeckler, G.; Balsiger, H.; Fisk, L. A.; Galvin, A. B.; Gliem, F.; Hamilton, D. C.; Ipavich, F. M.; Livi, S.; Mall, U.

    1992-01-01

    The ion composition in the Jovian environment was investigated with the Solar Wind Ion Composition Spectrometer on board Ulysses. A hot tenuous plasma was observed throughout the outer and middle magnetosphere. In some regions two thermally different components were identified. Oxygen and sulfur ions with several different charge states, from the volcanic satellite Io, make the largest contribution to the mass density of the hot plasma, even at high latitude. Solar wind particles were observed in all regions investigated. Ions from Jupiter's ionosphere were abundant in the middle magnetosphere, particularly in the high-latitude region on the dusk side, which was traversed for the first time.

  2. Magnetospheric and auroral plasmas: A short survey of progress, 1971 - 1975

    NASA Technical Reports Server (NTRS)

    Frank, L. A.

    1975-01-01

    Milestones in researches of auroral and magnetospheric plasmas for the past quadrennium 1971 - 1975 are reviewed. Findings, including those of the polar cusp, the polar wind, the explosive disruptions of the magnetotail, the interactions of hot plasmas with the plasmapause, the auroral field-aligned currents, and the striking 'inverted-V' electron precipitation events, are reported. Solutions to major questions concerning the origins and acceleration of these plasmas are discussed. A comprehensive bibliography of current research is included.

  3. System Effects of Ionospheric-Magnetospheric Plasma Redistribution During Storms (Invited)

    NASA Astrophysics Data System (ADS)

    Lotko, W.

    2009-12-01

    How does the magnetospheric uptake of ionospheric plasma change during storms, while the underlying ionosphere is modified by enhanced convection, precipitation and outflow? How does the outflow influence the dynamics and coupling of the magnetosphere and ionosphere, including plasma and geomagnetic field conditions of the lobes, plasmasheet and inner magnetosphere, and the evolution of the ionospheric conductance, temperature, and density? This paper addresses these questions by synthesizing results from selected presentations of the session. Observations of the F-region plasma and particle measurements in the low-altitude, high-latitude magnetosphere, lobes and plasmasheet are combined with results from ion outflow models, global kinetic models, ring-current models, and global geospace simulations. The synthesis shows that stormtime ionospheric outflows are superfluent in the cusp region with an upper flux limit of 1014 ions/m2-s. O+ beams appear in the lobes before interplanetary shock impact, and they exhibit dawn-dusk and hemispherical asymmetries, also manifested in the plasmasheet. The outflows enhance the stormtime ring current, relative to a system state with no ionospheric outflow. The distribution and intensity of the ring-current pressure depends also on the convection and the self-consistently induced magnetic field. In global simulations, the outflows modify dayside and nightside reconnection, precipitating electron power, the ionospheric conductance, the transpolar potential, and the electrodynamics of the magnetosphere-ionosphere interaction.

  4. The kappa Distribution as Tool in Investigating Hot Plasmas in the Magnetospheres of Outer Planets

    NASA Astrophysics Data System (ADS)

    Krimigis, S. M.; Carbary, J. F.

    2014-12-01

    The first use of a Maxwellian distribution with a high-energy tail (a κ-function) was made by Olbert (1968) and applied by Vasyliunas (1968) in analyzing electron data. The k-function combines aspects of both Maxwellian and power law forms to provide a reasonably complete description of particle density, temperature, pressure and convection velocity, all of which are key parameters of magnetospheric physics. Krimigis et al (1979) used it to describe flowing plasma ions in Jupiter's magnetosphere measured by Voyager 1, and obtained temperatures in the range of 20 to 35 keV. Sarris et al (1981) used the κ-function to describe plasmas in Earth's distant plasma sheet. The κ-function, in various formulations and names (e. g., γ-thermal distribution, Krimigis and Roelof, 1983) has been used routinely to parametrize hot, flowing plasmas in the magnetospheres of the outer planets, with typical kT ~ 10 to 50 keV. Using angular measurements, it has been possible to obtain pitch angle distributions and convective flow directions in sufficient detail for computations of temperatures and densities of hot particle pressures. These 'hot' pressures typically dominate the cold plasma pressures in the high beta (β > 1) magnetospheres of Jupiter and Saturn, but are of less importance in the relatively empty (β < 1) magnetospheres of Uranus and Neptune. Thus, the κ-function represents an effective tool in analyzing plasma behavior in planetary magnetospheres, but it is not applicable in all plasma environments. References Olbert, S., in Physics of the Magnetosphere, (Carovillano, McClay, Radoski, Eds), Springer-Verlag, New York, p. 641-659, 1968 Vasyliunas, V., J. Geophys. Res., 73(9), 2839-2884, 1968 Krimigis, S. M., et al, Science 204, 998-1003, 1979 Sarris, E., et al, Geophys. Res. Lett. 8, 349-352, 1981 Krimigis, S. M., and E. C. Roelof, Physics of the Jovian Magnetosphere, edited by A. J. Dessler, 106-156, Cambridge University Press, New York, 1983

  5. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder

    NASA Technical Reports Server (NTRS)

    Haines, D. Mark; Reinisch, Bodo W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N(sub e)) as a function of height (the N(sub e) profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year (1958). The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N(sub e) profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al., 1992), has never been put into space. NASA's 1990 Space Physics Strategy Implementation Study "The NASA Space Physics Program from 1995 to 2010" suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung, 1993). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R(sub e) (Reiff et al., 1994; Calvert et al., 1995). Magnetospheric radio sounding from space will provide remote density measurements of

  6. Conductance Effects on Inner Magnetospheric Plasma Morphology: Model Comparisons with IMAGE EUV, MENA, and HENA Data

    NASA Technical Reports Server (NTRS)

    Liemohn, M.; Ridley, A. J.; Kozyra, J. U.; Gallagher, D. L.; Brandt, P. C.; Henderson, M. G.; Denton, M. H.; Jahn, J. M.; Roelof, E. C.; DeMajistre, R. M.

    2004-01-01

    Modeling results of the inner magnetosphere showing the influence of the ionospheric conductance on the inner magnetospheric electric fields during the April 17, 2002 magnetic storm are presented. Kinetic plasma transport code results are analyzed in combination with observations of the inner magnetospheric plasma populations, in particular those from the IMAGE satellite. Qualitative and quantitative comparisons are made with the observations from EW, MENA, and HENA, covering the entire energy range simulated by the model (0 to 300 keV). The electric field description, and in particular the ionospheric conductance, is the only variable between the simulations. Results from the data-model comparisons are discussed, detailing the strengths and weaknesses of each conductance choice for each energy channel.

  7. Hot plasma and energetic particles in the earth's outer magnetosphere: new understandings during the IMS

    SciTech Connect

    Baker, D.N.; Fritz, T.A.

    1984-01-01

    In this paper we review the major accomplishments made during the IMS period in clarifying magnetospheric particle variations in the region from roughly geostationary orbit altitudes into the deep magnetotail. We divide our review into three topic areas: (1) acceleration processes; (2) transport processes; and (3) loss processes. Many of the changes in hot plasmas and energetic particle populations are often found to be related intimately to geomagnetic storm and magnetospheric substorm effects and, therefore, substantial emphasis is given to these aspects of particle variations in this review. The IMS data, taken as a body, allow a reasonably unified view as one traces magnetospheric particles from their acceleration source through the plasma sheet and outer trapping regions and, finally, to their loss via ionospheric precipitation and ring current formation processes. It is this underlying, unifying theme which is pursued here. 52 references, 19 figures.

  8. The impact of Callisto's atmosphere on its plasma interaction with the Jovian magnetosphere

    NASA Astrophysics Data System (ADS)

    Liuzzo, Lucas; Feyerabend, Moritz; Simon, Sven; Motschmann, Uwe

    2015-11-01

    The interaction between Callisto's atmosphere and ionosphere with the surrounding magnetospheric environment is analyzed by applying a hybrid simulation code, in which the ions are treated as particles and the electrons are treated as a fluid. Callisto is unique among the Galilean satellites in its interaction with the ambient magnetospheric plasma as the gyroradii of the impinging plasma and pickup ions are large compared to the size of the moon. A kinetic representation of the ions is therefore mandatory to adequately describe the resulting asymmetries in the electromagnetic fields and the deflection of the plasma flow near Callisto. Multiple model runs are performed at various distances of the moon to the center of Jupiter's magnetospheric current sheet, with differing angles between the corotational plasma flow and the ionizing solar radiation. When Callisto is embedded in the Jovian current sheet, magnetic perturbations due to the plasma interaction are more than twice the strength of the background field and may therefore obscure any magnetic signal generated via induction in a subsurface ocean. The magnetic field perturbations generated by Callisto's ionospheric interaction are very similar at different orbital positions of the moon, demonstrating that local time is only of minor importance when disentangling magnetic signals generated by the magnetosphere-ionosphere interaction from those driven by induction. Our simulations also suggest that deflection of the magnetospheric plasma around the moon cannot alone explain the density enhancement of 2 orders of magnitude measured in Callisto's wake during Galileo flybys. However, through inclusion of an ionosphere surrounding Callisto, modeled densities in the wake are consistent with in situ measurements.

  9. Preliminary feasibility study of pallet-only mode for magnetospheric and plasmas in space payloads, volume 4

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Results of studies performed on the magnetospheric and plasma portion of the AMPS are presented. Magnetospheric and plasma in space experiments and instruments are described along with packaging (palletization) concepts. The described magnetospheric and plasma experiments were considered as separate entities. Instrumentation ospheric and plasma experiments were considered as separate entities. Instrumentation requirements and operations were formulated to provide sufficient data for unambiguous interpretation of results without relying upon other experiments of the series. Where ground observations are specified, an assumption was made that large-scale additions or modifications to existing facilities were not required.

  10. The Magnetospheric Multiscale Mission...Resolving Fundamental Processes in Space Plasmas

    NASA Technical Reports Server (NTRS)

    Curtis, S.

    1999-01-01

    The Magnetospheric Multiscale (MMS) mission is a multiple-spacecraft Solar-Terrestrial Probe designed to study the microphysics of magnetic reconnection, charged particle acceleration, and turbulence in key boundary regions of Earth's magnetosphere. These three processes, which control the flow of energy, mass, and momentum within and across plasma boundaries, occur throughout the universe and are fundamental to our understanding of astrophysical and solar system plasmas. Only in Earth's magnetosphere, however, are they readily accessible for sustained study through in-situ measurement. MMS will employ five co-orbiting spacecraft identically instrumented to measure electric and magnetic fields, plasmas, and energetic particles. The initial parameters of the individual spacecraft orbits will be designed so that the spacecraft formation will evolve into a three-dimensional configuration near apogee, allowing MMS to differentiate between spatial and temporal effects and to determine the three dimensional geometry of plasma, field, and current structures. In order to sample all of the magnetospheric boundary regions, MMS will employ a unique four-phase orbital strategy involving carefully sequenced changes in the local time and radial distance of apogee and, in the third phase, a change in orbit inclination from 10 degrees to 90 degrees. The nominal mission operational lifetime is two years. Launch is currently scheduled for 2006.

  11. Rate of radial transport of plasma in Saturn’s inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Hill, T. W.

    2009-12-01

    The Cassini Plasma Spectrometer (CAPS) and the Cassini Magnetospheric Imaging Instrument (MIMI) frequently observe longitudinally localized injection and drift dispersion of hot plasma in Saturn’s magnetosphere. These signatures provide direct evidence for the major convective process in the inner magnetosphere of a rapidly rotating planet, in which the radial transport of plasma comprises hot, tenuous plasma moving inward and cooler, denser plasma moving outward. These injection events have been found to occupy only a small fraction of the total available longitudinal space, indicating that the inflow speed is probably much larger than the outflow speed. We set the local corotation speed as the upper limit of inflow velocities, and deduce the corresponding radial velocities of the outflowing flux tubes by analyzing the width of injection structures and assuming that the total potential drop around a given L-shell is zero. We then estimate an upper limit to the plasma outward mass transport rate, which turns out to be somewhat larger than previous estimates of the Enceladus source rate (e.g., Pontius and Hill, 2006). An important assumption in this study is that the plasma is largely confined to a thin equatorial sheet, and we have applied a centrifugal scale height model developed by Hill and Michel [1976].

  12. Multifluid MHD Investigation of Plasma Production and Transport in Saturn's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Rajendar, A.; Paty, C. S.; Arridge, C. S.

    2014-12-01

    The dynamics of Saturn's inner magnetosphere are driven by the planet's strong magnetic field, rapid rotation rate, and interactions between magnetospheric plasma and Saturn's distributed neutral cloud. This cloud is composed mostly of water and OH molecules and primarily originates from the cryovolcanic plumes of Enceladus. Charge-exchange collisions between ions and neutrals result in a loss of momentum from the plasma, while photoionization and electron-impact ionization of neutrals produces new, slow-moving water group ions that are accelerated in the corotation direction by the J×Bforce associated with magnetosphere-ionosphere coupling currents. Unbalanced centrifugal stresses cause this newly-produced plasma to move radially outward, eventually leaving the magnetosphere. The characteristic signature of this process is the development of inward-moving fingers of hot, rarefied, outer magnetosphere plasma, as required by the conservation of magnetic flux. We investigate the dynamics of Saturn's inner magnetosphere using the latest iteration of the Saturn multifluid model with refined plasma-neutral interaction physics. Earlier versions of this model were used to investigate the external triggering of plasmoids and the interchange process using a fixed internal source rate. We use a static representation of Saturn's neutral cloud and modified multifluid MHD equations incorporating mass- and momentum-loading terms. Our collision physics calculations have been updated to include energy-dependent rate coefficients, and includes the ability to specify a radially-dependent suprathermal electron distribution to investigate ionization by this component. We validate our results using data from the Cassini Plasma Spectrometer and Magnetometer instruments (CAPS and MAG) during Saturn solstice. Inclusion of self-consistent ion-neutral interactions in our simulation allows us to examine the spatial and temporal variation in mass- and momentum-loading in the inner

  13. Nuclear burst plasma injection into the magnetosphere and resulting spacecraft charging

    NASA Technical Reports Server (NTRS)

    Pavel, A. L.; Cipolla, J. A.; Silevitch, M. B.; Golden, K. I.

    1977-01-01

    The passage of debris from a high altitude ( 400 km) nuclear burst over the ionospheric plasma is found to be capable of exciting large amplitude whistler waves which can act to structure a collisionless shock. This instability will occur in the loss cone exits of the nuclear debris bubble, and the accelerated ambient ions will freestream along the magnetic field lines into the magnetosphere. Using Starfish-like parameters and accounting for plasma diffusion and thermalization of the propagating plasma mass, it is found that synchronous orbit plasma fluxes of high temperature electrons (near 10 keV) will be significantly greater than those encountered during magnetospheric substorms. These fluxes will last for sufficiently long periods of time so as to charge immersed bodies to high potentials and arc discharges to take place.

  14. Modeling of the Convection and Interaction of Ring Current, Plasmaspheric and Plasma Sheet Plasmas in the Inner Magnetosphere

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching; Chen, Sheng-Hsien; Buzulukova, Natalia; Glocer, Alex

    2010-01-01

    Distinctive sources of ions reside in the plasmasphere, plasmasheet, and ring current regions at discrete energies constitute the major plasma populations in the inner/middle magnetosphere. They contribute to the electrodynamics of the ionosphere-magnetosphere system as important carriers of the global current system, in triggering; geomagnetic storm and substorms, as well as critical components of plasma instabilities such as reconnection and Kelvin-Helmholtz instability at the magnetospheric boundaries. Our preliminary analysis of in-situ measurements shoves the complexity of the plasmas pitch angle distributions at particularly the cold and warm plasmas, vary dramatically at different local times and radial distances from the Earth in response to changes in solar wind condition and Dst index. Using an MHD-ring current coupled code, we model the convection and interaction of cold, warm and energetic ions of plasmaspheric, plasmasheet, and ring current origins in the inner magnetosphere. We compare our simulation results with in-situ and remotely sensed measurements from recent instrumentation on Geotail, Cluster, THEMIS, and TWINS spacecraft.

  15. Ion Beam and Plasma Technology Development for Surface Modification at Los Alamos National Laboratory

    SciTech Connect

    Davis, H.A.; Munson, C.P.; Wood, B.P.; Bitteker, L.J.; Nastasi, M.A.; Rej, D.J.; Waganaar, W.J.; Walter, K.C.; Coates, D.M.; Schleinitz, H.M.

    1997-12-31

    We are developing two high-throughput technologies for materials modification. The first is a repetitive intense ion beam source for materials modification through rapid surface melt and resolidification (up to 10{sup 10} deg/sec cooling rates) and for ablative deposition of coatings. The short range of the ions (typically 0.1 to 5 micrometers) allows vaporization or melting at moderate beam energy density (typically 1-50 J/cm{sup 2}). A new repetitive intense ion beam accelerator called CHAMP is under development at Los Alamos. The design beam parameters are: E=200 keV, I=15 kA, {tau}=1 {micro}s, and 1 Hz. This accelerator will enable applications such as film deposition, alloying and mixing, cleaning and polishing, corrosion and wear resistance, polymer surface treatments, and nanophase powder synthesis. The second technology is plasma source ion implantation (PSII) using plasmas generated from both gas phase (using radio frequency excitation) and solid phase (using a cathodic arc) sources. We have used PSII to directly implant ions for surface modification or as method for generating graded interfaces to enhance the adhesion of surface coatings. Surfaces with areas of up to 16 m{sup 2} and weighing more than a thousand kilograms have been treated in the Los Alamos PSII chamber. In addition, PSII in combination with cathodic source deposition has been used to form highly adherent, thick Er{sub 2}O{sub 3} coatings on steel for reactive metal containment in casting. These coatings resist delamination under extreme mechanical and thermal stress.

  16. On the Azimuthal Variation of Core Plasma in the Equatorial Magnetosphere

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Craven, P. D.; Comfort, R. H.; Moore, T. E.

    1995-01-01

    Previous results of plasmapause position surveys have been synthesized into a description of the underlying global distribution of plasmasphere-like or core plasma densities unique to a steady state magnetosphere. Under these steady conditions, the boundary between high- and low-density regions is taken to represent the boundary between diurnal near-corotation and large-scale circulation streamlines that traverse the entire magnetosphere. Results indicate a boundary that has a pronounced bulge in the dusk sector that is rotated westward and markedly reduced in size at increased levels of geomagnetic activity (and presumably magnetospheric convection). The derived profile is empirical confirmation of an underlying 'tear drop' distribution of core plasma, which is valid only for prolonged steady conditions and is somewhat different from that associated with the simple superposition of sunward flow and corotation, both in its detailed shape and in its varying orientation. Variation away from the tear drop profile suggests that magnetospheric circulation departs from a uniform flow field, having a radial dependence with respect to the Earth that is qualitatively consistent with electrostatic shielding of the convection electric field and which is rotated westward at increased levels of geophysical activity.

  17. Large-Scale Mini-Magnetosphere Plasma Propulsion (M2P2) Experiments

    NASA Technical Reports Server (NTRS)

    Winglee, R. M.; Slough, J.; Ziemba, T.; Euripides, P.; Adrian, M. L.; Gallagher, D.; Craven, P.; Tomlinson, W.; Cravens, J.; Burch, J.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Mini-Magnetosphere Plasma Propulsion (M2P2) is an innovative plasma propulsion system that has the potential to propel spacecraft at unprecedented speeds of 50 to 80 km per second with a low-power requirement of approx. 1 kW per 100 kg of payload and approx. 1 kg of neutral gas [fuel] consumption per day of acceleration. Acceleration periods from several days to a few months are envisioned. High specific impulse and efficiency are achieved through coupling of the spacecraft to the 400 km per second solar wind through an artificial magnetosphere. The mini-magnetosphere or inflated magnetic bubble is produced by the injection of cold dense plasma into a spacecraft-generated magnetic field envelope. Magnetic bubble inflation is driven by electromagnetic processes thereby avoiding the material and deployment problems faced by mechanical solar sail designs, Here, we present the theoretical design of M2P2 as well as initial results from experimental testing of an M2P2 prototype demonstrating: 1) inflation of the dipole magnetic field geometry through the internal injection of cold plasma; and 2) deflection of and artificial solar wind by the prototype M2P2 system. In addition, we present plans for direct laboratory measurement of thrust imparted to a prototype M2P2 by an artificial solar wind during the summer of 2001.

  18. Large-Scale Mini-Magnetosphere Plasma Propulsion (M2P2) Experiments

    NASA Technical Reports Server (NTRS)

    Winglee, R. M.; Slough, J.; Ziemba, T.; Euripides, P.; Gallagher, D.; Craven, P.; Adrian, M. L.; Tomlinson, W.; Cravens, J.; Burch, J.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Mini-Magnetosphere Plasma Propulsion (M2P2) is an innovative plasma propulsion system that has the potential to propel spacecraft at unprecedented speeds of 50 to 80 km/s, with a low power requirement of approx. 1 kW per 100 kg of payload and -1 kg of neutral gas [fuel] consumption per day of acceleration. Acceleration periods from several days to a few months are envisioned. High specific impulse and efficiency are achieved through coupling of the spacecraft to the 400 km/s. solar wind through an artificial magnetosphere. The mini-magnetosphere or inflated magnetic bubble is produced by the injection of cold dense plasma into a spacecraft-generated magnetic field envelope. Magnetic bubble inflation is driven by electromagnetic processes thereby avoiding the material and deployment problems faced by mechanical solar sail designs. Here, we present the theoretical design of M2P2 as well as initial results from experimental testing of an M2P2 prototype demonstrating: 1) inflation of the dipole magnetic field geometry through the internal injection of cold plasma; and 2) deflection of and artificial solar wind by the prototype M2P2 system. In addition, we present plans for direct laboratory measurement of thrust imparted to a prototype M2P2 by an artificial solar wind during the summer of 2001.

  19. The magnetospheric clock of Saturn—A self-organized plasma dynamo

    SciTech Connect

    Olson, J.; Brenning, N.

    2013-08-15

    The plasma in the inner magnetosphere of Saturn is characterized by large-amplitude azimuthal density variations in the equatorial plane, with approximately a sinusoidal dependence on the azimuthal angle [D. A. Gurnett et al., Science 316, 442 (2007)]. This structure rotates with close to the period of the planet itself and has been proposed to steer other nonaxisymmetric phenomena, e.g., the Saturn kilometric radiation SKR [W. S. Kurth et al., Geophys. Res. Lett. 34, L02201 (2007)], and inner-magnetosphere magnetic field perturbations [D. J. Southwood and M. G. Kivelson, J. Geophys. Res. 112(A12), A12222 (2007)]. There is today no consensus regarding the basic driving mechanism. We here propose it to be a plasma dynamo, located in the neutral gas torus of Enceladus but coupled both inwards, through electric currents along the magnetic field lines down to the planet, and outwards through the plasma flow pattern there. Such a dynamo mechanism is shown to self-regulate towards a state that, with realistic parameters, can reproduce the observed configuration of the magnetosphere. This state is characterized by three quantities: the Pedersen conductivity in the polar cap, the ionization time constant in the neutral gas torus, and a parameter characterizing the plasma flow pattern. A particularly interesting property of the dynamo is that regular (i.e., constant-amplitude, sinusoidal) variations in the last parameter can lead to complicated, non-periodic, oscillations around the steady-state configuration.

  20. AMPS sciences objectives and philosophy. [Atmospheric, Magnetospheric and Plasmas-in-Space project on Spacelab

    NASA Technical Reports Server (NTRS)

    Schmerling, E. R.

    1975-01-01

    The Space Shuttle will open a new era in the exploration of earth's near-space environment, where the weight and power capabilities of Spacelab and the ability to use man in real time add important new features. The Atmospheric, Magnetospheric, and Plasmas-in-Space project (AMPS) is conceived of as a facility where flexible core instruments can be flown repeatedly to perform different observations and experiments. The twin thrusts of remote sensing of the atmosphere below 120 km and active experiments on the space plasma are the major themes. They have broader implications in increasing our understanding of plasma physics and of energy conversion processes elsewhere in the universe.

  1. Effect of the ponderomotive force caused by Alfvén waves on a background plasma in the dayside magnetosphere

    NASA Astrophysics Data System (ADS)

    Nekrasov, A. K.; Feygin, F. Z.

    2016-07-01

    The effect of the ponderomotive force on the background plasma modification near magnetic holes, which form at the dayside magnetospheric boundary under the action of the solar wind, has been studied. It was shown that this effect results in a substantial increase in a nonlinear plasma density disturbance. The dependence of the ponderomotive force on the magnetospheric parameters (the magnetic longitude, distance from the Earth's surface, ratio of the wave frequency to the proton gyrofrequency, and ionospheric ion cyclotron wave amplitude) has been studied. Nonlinear plasma density disturbances will be maximal in the region of magnetic holes, which are located in the dayside magnetosphere at λ ~ 0°-30° geomagnetic longitudes (λ = 0° corresponds to noon), where the effect of the solar wind pressure is maximal. A similar effect is also observed in the dependence of a nonlinear plasma density disturbance on other magnetospheric parameters.

  2. Characteristics of the Plasma Distribution in Mercury's Equatorial Magnetosphere Derived from MESSENGER Magnetic Field and Plasma Observations

    NASA Astrophysics Data System (ADS)

    Korth, H.; Anderson, B. J.; Johnson, C. L.; Winslow, R. M.; Raines, J. M.; Slavin, J. A.; Purucker, M. E.; Zurbuchen, T.; Solomon, S. C.; McNutt, R. L.

    2012-12-01

    Localized reductions in the magnetic field associated with plasma pressure in Mercury's plasma sheet have been routinely observed by the Magnetometer on the MErcury Surface, Space ENvironment, Geochemistry, and Ranging (MESSENGER) spacecraft. We present a statistical analysis of near-equatorial magnetic depressions to derive the structure of Mercury's plasma sheet pressure. Because the plasma pressure in the magnetosphere correlates with solar wind density, the pressures were normalized to a Mercury heliocentric distance of 0.39 AU. A model magnetic field was used to map observations obtained on the ascending and descending orbit nodes to the magnetic equator, and the mapped equatorial distribution revealed the presence of plasma in a toroidal section extending on the nightside from dusk to dawn. Mapping the data to invariant magnetic latitude shows that the pressure is symmetric about the magnetic equator. The average pressure normalized for heliocentric distance is 1.45 nPa and exhibits a weak, 0.05 nPa/h, dusk-to-dawn gradient with local time. The plasma sheet pressure can vary between successive orbits by an order of magnitude. Unlike the predictions of some global simulations of Mercury's magnetosphere but consistent with observations by MESSENGER's Fast Imaging Plasma Spectrometer, the plasma enhancements do not form a closed distribution around the planet. This difference may arise from the idealized solar wind and interplanetary magnetic field conditions used in the simulations, conditions that maximize the size and stability of the magnetosphere and thus promote the formation of drift paths that close around the planet. For typical plasma sheet energies, 5 keV, the first adiabatic invariant for protons fails to be conserved even within 500 km altitude at midnight, implying that stochastic processes must be considered in plasma sheet transport.

  3. Climatology of high-β plasma measurements in Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Cohen, Ross; Gerrard, Andrew J.; Lanzerotti, Louis J.; Soto-Chavez, A. R.; Kim, Hyomin; Manweiler, Jerry W.

    2017-01-01

    Since their launch in August 2012, the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instruments on the NASA Van Allen Probes spacecraft have been making continuous high-resolution measurements of Earth's ring current plasma environment. After a full traversal through all magnetic local times, a climatology (i.e., a survey of observations) of high-beta (β) plasma events (defined here as β > 1) as measured by the RBSPICE instrument in the ˜45 keV to ˜600 keV proton energy range in the inner magnetosphere (L < 5.8) has been constructed. In this paper we report this climatology of such high-β plasma occurrences, durations, and their general characteristics. Specifically, we show that most high-β events in the RBSPICE energy range are associated with postdusk/premidnight sector particle injections or plasma patches and can last from minutes to hours. While most of these events have a β less than 2, there are a number of observations reaching β greater than 4. Other observations of particular note are high-β events during relatively minor geomagnetic storms and examples of very long duration high-β plasmas. We show that high-β plasmas are a relatively common occurrence in the inner magnetosphere during both quiet and active times. As such, the waves generated by these plasmas may have an underappreciated role in the inner magnetosphere, and thus the study of these plasmas and their instabilities may be more important than has been currently addressed.

  4. Generation of auroral kilometric radiation in inhomogeneous magnetospheric plasma

    NASA Astrophysics Data System (ADS)

    Burinskaya, T. M.; Shevelev, M. M.

    2017-01-01

    The generation of auroral kilometric radiation in a narrow 3D plasma cavity, in which a weakly relativistic electron flow is propagated along the magnetic field against a low-density cold background plasma, is studied. The time dynamics of the propagation and intensification of waves are analyzed using geometric optics equations. The waves have different wave vector components and start from the cavity center at an altitude of about the Earth's radius at plasma parameters typical for the auroral zone at this altitude. It is shown that the global inhomogeneity of the Earth's magnetic field is of key importance in shaping the auroral kilometric radiation spectra.

  5. Some contributions to knowledge of the magnetospheric plasma by ISEE investigators

    NASA Technical Reports Server (NTRS)

    Ogilvie, K. W.

    1984-01-01

    The ISEE project has made substantial contributions to the knowledge of the magnetosphere during the period of the IMS, especially in the discipline of Space Plasma Physics. Results obtained during approximately the first two years of the operation of ISEE-1 and -2, and touches on relevant results of ISEE-3 are reviewed. The ability to control the separation between ISEE-1 and -2, which are in nearly identical orbits, has permitted study of the motion and structure of the bow shock and magnetopause, the boundary layers, and the plasma sheet. Much evidence was obtained favoring the existence of reconnection and its relevance to the transfer of magnetic flux from the frontside to the rear of the magnetosphere, although not everyone agrees that it is the only important process. The presence of both reflected and accelerated particles was shown to lead to the development of a foreshock region between the bow shock and the interplanetary magnetic field line tangential to it.

  6. Distribution of plasma and magnetic field in the Venus induced magnetosphere is strongly asymmetrical

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Zhang, T.-L.; Woch, J.; Wei, Y.; Fedorov, A.; Barabash, S.; Lundin, R.

    2013-09-01

    Venus Express spacecraft have provided us a wealth of in-situ observations of characteristics of induced magnetosphere of Venus. One of its important features is a distinct asymmetry in plasma and field characteristics between the hemisphere pointed in the direction of the motional electric field and the opposite hemisphere. Asymmetry starts from formation of the magnetic barrier, then continues to low altitudes where effects of finite conductivity become important and further to the near Venus tail where the magnetic tail and plasma sheet are formed. As a result, the structure and dynamics of the induced magnetosphere in both hemispheres occur different. We present different aspects of such an asymmetry and discuss possible mechanisms of its appearance.

  7. Distribution of plasma and magnetic field in the Venus induced magnetosphere is strongly asymmetrical

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Zhang, T.; Woch, J. G.; Wei, Y.; Fedorov, A.; Barabash, S. V.; Lundin, R. N.

    2013-12-01

    Venus Express spacecraft have provided us a wealth of in-situ observations of characteristics of induced magnetosphere of Venus. One of its important features is a distinct asymmetry in plasma and field characteristics between the hemisphere pointed in the direction of the motional electric field and the opposite hemisphere. Asymmetry starts from formation of the magnetic barrier, then continues to low altitudes where effects of finite conductivity become important and further to the near Venus tail where the magnetic tail and plasma sheet are formed. As a result, the structure and dynamics of the induced magnetosphere in both hemispheres occur different. We present different aspects of such an asymmetry and discuss possible mechanisms of its appearance.

  8. Ion cyclotron heating experiments in magnetosphere plasma device RT-1

    NASA Astrophysics Data System (ADS)

    Nishiura, M.; Yoshida, Z.; Yano, Y.; Kawazura, Y.; Saitoh, H.; Yamasaki, M.; Mushiake, T.; Kashyap, A.; Takahashi, N.; Nakatsuka, M.; Fukuyama, A.

    2015-12-01

    The ion cyclotron range of frequencies (ICRF) heating with 3 MHz and ˜10 kW is being prepared in RT-1. The operation regime for electron cyclotron resonance (ECR) heating is surveyed as the target plasmas. ECRH with 8.2 GHz and ˜50 kW produces the plasmas with high energy electrons in the range of a few ten keV, but the ions still remain cold at a few ten eV. Ion heating is expected to access high ion beta state and to change the aspect of plasma confinement theoretically. The ICRF heating is applied to the target plasma as an auxiliary heating. The preliminary result of ICRF heating is reported.

  9. Ion cyclotron heating experiments in magnetosphere plasma device RT-1

    SciTech Connect

    Nishiura, M. Yoshida, Z.; Yano, Y.; Kawazura, Y.; Saitoh, H.; Yamasaki, M.; Mushiake, T.; Kashyap, A.; Takahashi, N.; Nakatsuka, M.; Fukuyama, A.

    2015-12-10

    The ion cyclotron range of frequencies (ICRF) heating with 3 MHz and ∼10 kW is being prepared in RT-1. The operation regime for electron cyclotron resonance (ECR) heating is surveyed as the target plasmas. ECRH with 8.2 GHz and ∼50 kW produces the plasmas with high energy electrons in the range of a few ten keV, but the ions still remain cold at a few ten eV. Ion heating is expected to access high ion beta state and to change the aspect of plasma confinement theoretically. The ICRF heating is applied to the target plasma as an auxiliary heating. The preliminary result of ICRF heating is reported.

  10. Magnetosphere-ionosphere interactions: Near Earth manifestations of the plasma universe

    NASA Technical Reports Server (NTRS)

    Faelthammar, Carl-Gunne

    1986-01-01

    As the universe consists almost entirely of plasma, the understanding of astrophysical phenomena must depend critically on the understanding of how matter behaves in the plasma state. In situ observations in the near Earth cosmical plasma offer an excellent opportunity of gaining such understanding. The near Earth cosmical plasma not only covers vast ranges of density and temperature, but is the site of a rich variety of complex plasma physical processes which are activated as a results of the interactions between the magnetosphere and the ionosphere. The geomagnetic field connects the ionosphere, tied by friction to the Earth, and the magnetosphere, dynamically coupled to the solar wind. This causes an exchange of energy an momentum between the two regions. The exchange is executed by magnetic-field-aligned electric currents, the so-called Birkeland currents. Both directly and indirectly (through instabilities and particle acceleration) these also lead to an exchange of plasma, which is selective and therefore causes chemical separation. Another essential aspect of the coupling is the role of electric fields, especially magnetic field aligned (parallel) electric fields, which have important consequences both for the dynamics of the coupling and, especially, for energization of charged particles.

  11. Dynamics of plasma density perturbations in the upper ionosphere and the magnetosphere under the action of powerful HF radio waves

    NASA Astrophysics Data System (ADS)

    Borisov, N.; Ryabova, N.; Ruzhin, Yu.

    2015-11-01

    Dynamics of the density perturbations of the main plasma components (electrons, oxygen and hydrogen ions) in the upper ionosphere and the magnetosphere under the action of powerful HF radio waves is discussed theoretically and numerically. For finite heating pulse and different effective powers the variations of the density perturbations in time at various heights are investigated. We argue that due to collisionless damping the magnetospheric duct along the whole field line is not formed. Instead positive and negative perturbations of the main plasma components propagating with the attenuation in the magnetosphere with two different speeds are predicted. Utilization of pulsed heating provides significant information concerning plasma perturbations in the upper ionosphere and the magnetosphere.

  12. Direct measurements of the magnetic field inside the magnetospheric plasma RT-1

    NASA Astrophysics Data System (ADS)

    Yano, Yoshihisa; Yoshida, Zensho; Morikawa, Junji; Saitoh, Haruhiko; Mizushima, Tatsunori

    2009-11-01

    The magnetospheric plasma experiment RT-1 (Ring trap -1) has achieved stable confinement of high-beta plasma produced by electron cyclotron resonance heating (ECH). The observed diamagnetic signals (˜3mWb) correspond to the maximum local beta values exceeding 40%, according to the MHD equilibrium analysis. (Soft X-ray measurements confirmed the existence of high energy electrons of Te ˜ 10 keV, which is consistent to the estimated plasma pressure.) As a diagnostic of internal profile of the plasma pressure, we developed a multi-channel magnetic probe system and carried out direct measurement of the diamagnetic signals inside the plasma. We found that the pressure profile peaks steeply near the ECH resonance surface and has dependence on the fueling gas pressure.

  13. Kinetic simulation of plasma flows in the inner magnetosphere

    NASA Technical Reports Server (NTRS)

    Miller, Ronald H.; Rasmussen, Craig E.; Gombosi, Tamas I.; Khazanov, Georgi V.; Winske, Dan

    1993-01-01

    A one-dimensional hybrid particle code is used to study the interactions between upflowing thermal ions from conjugate ionospheres. The simulation model allows for multiple species, convection of plasmaspheric flux tubes, and Coulomb self-collisions which conserve momentum and energy locally. The model incorporates a variable-flux boundary condition where the flux, at the boundaries, approaches zero as the plasmasphere fills and equilibrium conditions are reached. The effects of two important processes on plasmaspheric refilling have been considered. The first includes convection of the plasmaspheric flux tube. The second is the interaction of ionospheric thermal plasma and particle injection from an external source. Particle injection seems to play an important role in the evolution of the total particle distribution on the early timescales (t less than 1 hour); however, for late timescales (t larger than 8 days) the thermal plasma from the ionosphere dominates the particle distribution.

  14. Effects of Nonconvective Electric Fields on Magnetospheric Plasma Dynamics.

    DTIC Science & Technology

    1983-01-31

    collaborative effort will be established in this area. Finally we will continue our work on the dynamic properties of auroral double layers and... efforts with members of the Department of Plasma Physics, Royal Institute of Technology, Stockholm, Sweden. We have also completed a study of small...scale auroral vortices as observed by Air Force satellite S3-2. This work was a collaborative effort with scientists at AFGL. Ancon~sio For. T.rlZC TS

  15. Magnetic Dipole Inflation with Cascaded ARC and Applications to Mini-Magnetospheric Plasma Propulsion

    NASA Technical Reports Server (NTRS)

    Giersch, L.; Winglee, R.; Slough, J.; Ziemba, T.; Euripides, P.

    2003-01-01

    Mini-Magnetospheric Plasma Propulsion (M2P2) seeks to create a plasma-inflated magnetic bubble capable of intercepting significant thrust from the solar wind for the purposes of high speed, high efficiency spacecraft propulsion. Previous laboratory experiments into the M2P2 concept have primarily used helicon plasma sources to inflate the dipole magnetic field. The work presented here uses an alternative plasma source, the cascaded arc, in a geometry similar to that used in previous helicon experiments. Time resolved measurements of the equatorial plasma density have been conducted and the results are discussed. The equatorial plasma density transitions from an initially asymmetric configuration early in the shot to a quasisymmetric configuration during plasma production, and then returns to an asymmetric configuration when the source is shut off. The exact reasons for these changes in configuration are unknown, but convection of the loaded flux tube is suspected. The diffusion time was found to be an order of magnitude longer than the Bohm diffusion time for the period of time after the plasma source was shut off. The data collected indicate the plasma has an electron temperature of approximately 11 eV, an order of magnitude hotter than plasmas generated by cascaded arcs operating under different conditions. In addition, indirect evidence suggests that the plasma has a beta of order unity in the source region.

  16. Proton interaction with quasi-electrostatic whistler mode waves in an inhomogeneous plasma (magnetosphere)

    NASA Astrophysics Data System (ADS)

    Shklyar, D. R.; Titova, E. E.

    2017-01-01

    We study the interaction between energetic protons of the Earth's radiation belts and quasi-electrostatic whistler mode waves. The nature of these waves is well known: whistler waves, which are excited in the magnetosphere due to cyclotron instability, enter the resonant regime of propagation and become quasielectrostatic, while their amplitude significantly increases. Far enough from the equator where proton gyrofrequency and transversal velocity increase the nonlinear interaction between these waves and energetic protons becomes possible. We show that plasma inhomogeneity may destroy cyclotron resonance between wave and proton on the time scale of the order of particle gyroperiod which in fact means the absence of cyclotron resonance; nevertheless, the interaction between waves and energetic particles remains nonlinear. In this case, particle dynamics in the phase space has the character of diffusion; however, the diffusion coefficients are determined by the averaged amplitude of the wave field, but not by its resonant harmonics. For real parameters of the waves and magnetospheric plasma, proton pitch-angle diffusion leading to their precipitation from the magnetosphere becomes essential.

  17. Radial diffusion of low-energy plasma ions in Saturn's magnetosphere

    NASA Astrophysics Data System (ADS)

    Barbosa, D. D.

    1990-10-01

    Radial diffusion of low-energy plasma ions in Saturn's magnetosphere is investigated using a comprehensive set of equations for radial diffusion that incorporate distributed sources and sinks of ions. The results of calculations indicate that the radial-diffusion transport of low-energy O(+) ions with a source in the neutral H2O cloud of the satellites Dione and Tethys can account for Voyager observations of thermal heavy ions in Saturn's magnetosphere. The source rate was calculated to be about 10 to the 26th O(+) ions/sec, in good agreement with the sputtering calculations of Johnson et al. (1989). It is estimated that, due to fast radial diffusion, the residence time of O(+) ions in the Dione-Tethys torus is about 30 days, sufficiently short to account for the plasma density observed there. The densities of hot H(+) and N(+) resulting from the ionization and pickup of Titan's neutral clouds in the outer magnetosphere can also be accounted for within the framework of diffusive ion transport.

  18. Radial energy transport by magnetospheric ULF waves: Effects of magnetic curvature and plasma pressure

    NASA Technical Reports Server (NTRS)

    Kouznetsov, Igor; Lotko, William

    1995-01-01

    The 'radial' transport of energy by internal ULF waves, stimulated by dayside magnetospheric boundary oscillations, is analyzed in the framework of one-fluid magnetohydrodynamics. (the term radial is used here to denote the direction orthogonal to geomagnetic flux surfaces.) The model for the inhomogeneous magnetospheric plasma and background magnetic field is axisymmetric and includes radial and parallel variations in the magnetic field, magnetic curvature, plasma density, and low but finite plasma pressure. The radial mode structure of the coupled fast and intermediate MHD waves is determined by numerical solution of the inhomogeneous wave equation; the parallel mode structure is characterized by a Wentzel-Kramer-Brillouin (WKB) approximation. Ionospheric dissipation is modeled by allowing the parallel wave number to be complex. For boudnary oscillations with frequencies in the range from 10 to 48 mHz, and using a dipole model for the background magnetic field, the combined effects of magnetic curvature and finite plasma pressure are shown to (1) enhance the amplitude of field line resonances by as much as a factor of 2 relative to values obtained in a cold plasma or box-model approximation for the dayside magnetosphere; (2) increase the energy flux delivered to a given resonance by a factor of 2-4; and (3) broaden the spectral width of the resonance by a factor of 2-3. The effects are attributed to the existence of an 'Alfven buoyancy oscillation,' which approaches the usual shear mode Alfven wave at resonance, but unlike the shear Alfven mode, it is dispersive at short perpendicular wavelengths. The form of dispersion is analogous to that of an internal atmospheric gravity wave, with the magnetic tension of the curved background field providing the restoring force and allowing radial propagation of the mode. For nominal dayside parameters, the propagation band of the Alfven buoyancy wave occurs between the location of its (field line) resonance and that of the

  19. Plasma in Saturn's Nightside Magnetosphere and the Implications for Global Circulation

    NASA Technical Reports Server (NTRS)

    McAndrews, H.J.; Thomsen, M.F.; Arridge, C.S.; Jackman, C.M.; Wilson, R.J.; Henderson, M.G.; Tokar, R.L.; Khurana, K.K.; Sittler, E. C.; Coates, A.J.; Dougherty, M.K.

    2009-01-01

    We present a bulk ion flow map from the nightside, equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50RS. The plasma characteristics in the near-midnight region are described and indicate a transition between the region of the magnetosphere containing plasma on closed drift paths and that containing flux tubes which may not complete a full rotation around the planet. Data from the electron spectrometer reveal two plasma states of high and low density. These are attributed either to the sampling of mass-loaded and depleted flux tubes, respectively, or to the latitudinal structure of the plasma sheet. Depleted, returning flux tubes are not, in general, directly observed in the ions, although the electron observations suggest that such a process must take place in order to produce the low-density population. Flux-tube content is conserved below a limit defined by the mass-loading and magnetic field strength and indicates that the flux tubes sampled may survive their passage through the tail. The conditions for mass-release are evaluated using measured densities, angular velocities and magnetic field strength. The results suggest that for the relatively dense ion populations detectable by the ion mass spectrometer (IMS), the condition for flux-tube breakage has not yet been exceeded. However, the low-density regimes observed in the electron data suggest that loaded flux tubes at greater distances do exceed the threshold for mass-loss and subsequently return to the inner magnetosphere significantly depleted of plasma.

  20. Plasma in Saturn's nightside magnetosphere and the implications for global circulation

    SciTech Connect

    Mcandrews, Hazel J; Wilson, R J; Henderson, M G; Tokar, R L; Jackman, C M; Khurana, K K; Sittler, E C; Dougherty, M K

    2009-01-01

    We present a bulk ion flow map from the nightside equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50 R{sub s}. The plasma characteristics in the near-midnight region are described and indicate a transition between the region of the magnetosphere containing plasma on closed drift paths and that containing flux tubes which may not complete a full rotation around the planet. Data from the electron spectrometer reveal two plasma states of high and low density. These are attributed either to the sampling of mass-loaded and depleted flux tubes, respectively, or to the latitudinal structure of the plasma sheet Depleted, returning flux tubes are not, in general, directly observed in the ions, although the electron observations suggest that such a process must take place in order to produce the low density population. Flux tube content is conserved below a limIt defined by the mass-loading and magnetic field strength and indicates that the flux tubes sampled may survive their passage through the tail. The conditions for mass release are evaluated using measured densities, angular velocities and magnetic field strength, The results suggest that for the relatively dense ion populations detectable by IMS, the condition for flux-tube breakage has not yet been exceeded, However, the low-density regimes observed in the electron data suggest that loaded flux tubes at greater distances do exceed the threshold for mass loss and subsequently return to the inner magnetosphere significantly depleted of plasma.

  1. Plasma in Saturn's nightside magnetosphere and the implications for global circulation

    NASA Astrophysics Data System (ADS)

    McAndrews, H. J.; Thomsen, M. F.; Arridge, C. S.; Jackman, C. M.; Wilson, R. J.; Henderson, M. G.; Tokar, R. L.; Khurana, K. K.; Sittler, E. C.; Coates, A. J.; Dougherty, M. K.

    2009-12-01

    We present a bulk ion flow map from the nightside, equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50 RS. The plasma characteristics in the near-midnight region are described and indicate a transition between the region of the magnetosphere containing plasma on closed drift paths and that containing flux tubes which may not complete a full rotation around the planet. Data from the electron spectrometer reveal two plasma states of high and low density. These are attributed either to the sampling of mass-loaded and depleted flux tubes, respectively, or to the latitudinal structure of the plasma sheet. Depleted, returning flux tubes are not, in general, directly observed in the ions, although the electron observations suggest that such a process must take place in order to produce the low-density population. Flux-tube content is conserved below a limit defined by the mass-loading and magnetic field strength and indicates that the flux tubes sampled may survive their passage through the tail. The conditions for mass-release are evaluated using measured densities, angular velocities and magnetic field strength. The results suggest that for the relatively dense ion populations detectable by the ion mass spectrometer (IMS), the condition for flux-tube breakage has not yet been exceeded. However, the low-density regimes observed in the electron data suggest that loaded flux tubes at greater distances do exceed the threshold for mass-loss and subsequently return to the inner magnetosphere significantly depleted of plasma.

  2. Plasma in Saturn's nightside magnetosphere and the implications for global circulation

    SciTech Connect

    Mcandrews, Hazel J; Thomsen, Michelle F; Wilson, Robert J; Henderson, Michael G; Tokar, Robert L; Arridge, Chris S; Khurana, Krishan K; Sittler, Edward C; Coates, Andrew J; Dougherty, Michele K

    2008-01-01

    We present a bulk ion flow map from the nightside, equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50 RS. The plasma characteristics in the near-midnight region are described and indicate a transition between the region of the magnetosphere containing plasma on closed drift paths and that containing flux tubes which may not complete a full rotation around the planet. Data from the electron spectrometer reveal two plasma states of high and low density. These are attributed either to the sampling of mass-loaded and depleted flux tubes, respectively, or to the latitudinal structure of the plasma sheet. Depleted, returning flux tubes are not, in general, directly observed in the ions, although the electron observations suggest that such a process must take place in order to produce the low density population. An example of such a low-density interval containing hot electrons with a dipolarised, swept-forward field configuration is described and strongly suggests that reconnection must have occurred planetward of Cassini. Flux tube content is conserved below a limit defined by the mass-loading and magnetic field strength and indicates that the flux tubes sampled may survive their passage through the tail. The conditions for mass release are evaluated using measured densities, angular velocities and magnetic field strength. The results suggest that for the relatively dense ion populations detectable by IMS, the condition for flux-tube breakage has not yet been exceeded. However, the low-density regimes observed in the electron data suggest that loaded flux tubes at greater distances do exceed the threshold for mass loss and subsequently return to the inner magnetosphere significantly depleted of plasma.

  3. Magnetospheric plasma flows associated with boundary waves and flux transfer events

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Smith, M. F.

    1992-01-01

    We describe plasma flow perturbations in the outer magnetosphere during the passage of magnetopause boundary waves and cylindrically shaped flux transfer events (FTEs). Spacecraft which remain within the magnetosphere observe bipolar flows normal to the nominal magnetopause accompanied by flows nearly opposite to the direction of boundary wave and/or FTE motion. Flows are generally discontinuous across FTE and magnetopause boundaries, with reversals in the component of flow tangential to the nominal magnetopause expected during all magnetopause crossings and some entries into FTEs. No bipolar flows normal to the nominal magnetopause occur within FTEs unless they rotate and none occur in the magnetosheath unless the boundary waves propagate relative to the magnetosheath flow. IRM satellite observations on October 28, 1984 may be interpreted either in terms of FTEs or boundary waves.

  4. Theories of radio emissions and plasma waves. [in Jupiter magnetosphere

    NASA Technical Reports Server (NTRS)

    Goldstein, M. L.; Goertz, C. K.

    1983-01-01

    The complex region of Jupiter's radio emissions at decameter wavelengths, the so-called DAM, is considered, taking into account the basic theoretical ideas which underly both the older and newer theories and models. Linear theories are examined, giving attention to direct emission mechanisms, parallel propagation, perpendicular propagation, and indirect emission mechanisms. An investigation of nonlinear theories is also conducted. Three-wave interactions are discussed along with decay instabilities, and three-wave up-conversio. Aspects of the Io and plasma torus interaction are studied, and a mechanism by which Io can accelerate electrons is reviewed.

  5. Self-consistent electrostatic potential due to trapped plasma in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Miller, Ronald H.; Khazanov, George V.

    1993-01-01

    A steady state solution for the self-consistent electrostatic potential due to a plasma confined in a magnetic flux tube is considered. A steady state distribution function is constructed for the trapped particles from the constants of the motion, in the absence of waves and collisions. Using Liouville's theorem, the particle density along the geomagnetic field is determined and found to depend on the local magnetic field, self-consistent electric potential, and the equatorial plasma distribution function. A hot anisotropic magnetospheric plasma in steady state is modeled by a bi-Maxwellian at the equator. The self-consistent electric potential along the magnetic field is calculated assuming quasineutrality, and the potential drop is found to be approximately equal to the average kinetic energy of the equatorially trapped plasma. The potential is compared with that obtained by Alfven and Faelthammar (1963).

  6. Electrostatic ion-cyclotron waves in magnetospheric plasmas Nonlocal aspects

    NASA Technical Reports Server (NTRS)

    Ganguli, G.; Bakshi, P.; Palmadesso, P.

    1984-01-01

    The importance of the effect of the magnetic shear and the finite size of current channel on the electrostatic ion-cyclotron instability for the space plasmas is illustrated. A non-local treatment is used. When the channel width Lc, is larger than the shear length Ls, there is a large reduction in the growth rate along with a noteworthy reduction of the band of the unstable perpendicular wavelengths. For Lc less than or = Ls/10 the growth rate is not much altered from its local value, however for Lc/pi i less than or = 10 to the second power the growth rate starts falling below the local value and vanishes for Lc pi i. The non-local effects lead to enhanced coherence in the ion cyclotron waves. Previously announced in STAR as N84-14917

  7. Response of the inner magnetosphere and the plasma sheet to a sudden impulse

    NASA Astrophysics Data System (ADS)

    Keika, K.; Nakamura, R.; Baumjohann, W.; Runov, A.; Takada, T.; Volwerk, M.; Zhang, T. L.; Klecker, B.; Lucek, E. A.; Carr, C.; RèMe, H.; Dandouras, I.; André, M.; Frey, H.

    2008-07-01

    The passage of an interplanetary shock caused a sudden compression of the magnetosphere between 0900 UT and 0915 UT on 24 August 2005. An estimate of the shock normal from solar wind data obtained by Geotail upstream of the bow shock indicates symmetric compression with respect to the noon-midnight meridian. Compression-related disturbances of the magnetic and electric field and plasma motion were observed by Double Star Program (DSP) Tan Ce 1 (TC1) and Tan Ce 2 (TC2) in the inner magnetosphere and by the Cluster spacecraft in the dawnside plasma sheet. DSP/TC1 and TC2 observations suggest that the disturbances in the inner magnetosphere are propagating from the dayside magnetopause. Cluster S/C 4 observations indicate that the front normal of the disturbances in the dawnside plasma sheet is ϕ ˜ 180° at 0902:50 UT and ϕ = 107° at 0904:34 UT, where ϕ is the longitude in GSM coordinates, if we assume that the measured electric field is on the front plane and the normal lies on the X-Y plane. The timing analysis applied to magnetic field data from the four Cluster spacecraft independently gives a front normal, which is calculated to be ϕ = 131° at about 0904:20 UT. Shock-associated magnetic and electric field disturbances propagating from both the dayside and flank magnetopauses are detected in the plasma sheet; the latter makes the dominant contribution. Substorms are, however, not triggered at the passage of the disturbances.

  8. Research on solar-wind and magnetospheric electric fields and plasmas

    NASA Technical Reports Server (NTRS)

    Burch, J. L.

    1978-01-01

    Attempts were made to determine the role of the interplanetary magnetic field in controlling: (1) particle acceleration processes in the earth's polar cap; (2) plasma convection patterns at high latitudes; and, (3) the topology of magnetic field lines in the earth's polar cusps. The primary result of the study on polar-cap particle acceleration regions was that they tend to occur in only one polar cap at a time, and that they occur in the hemisphere for which the magnetospheric tail-lobe field lines have solar-magnetospheric x components that are antiparallel to those of the interplanetary and tail-lobe magnetic field. Southward-directed interplanetary magnetic fields give rise to broad convection throats which cover several hours of local time across the dayside cleft. Under such conditions, solar-wind plasma is channeled efficiently through the polar cusps to populate the plasma mantle and dayside boundary layer. On the other hand, the appearance of strong northward components in the interplanetary magnetic field result in a very constricted throat, resulting in inefficient plasma entry at the cusps by diffusion processes.

  9. A Model for Plasma Transport in a Corotation-Dominated Magnetosphere.

    NASA Astrophysics Data System (ADS)

    Pontius, Duane Henry, Jr.

    1988-06-01

    The gross structures of the magnetospheres of the outer planets are decided by processes quite different from those predominant in that of the earth. The terrestrial plasmapause, the boundary beyond which plasma motion is principally determined by magnetospheric interaction with the solar wind, is typically inside geosynchronous orbit. Within the plasmasphere, rotational effects are present, but gravity exceeds the centrifugal force of corotation. In contrast, the Jovian plasmasphere extends to a distance at least twenty times farther than synchronous orbit, affording a large region where rotational effects are expected to he clearly manifest (Brice and Ioannidis, 1970). The goal of this thesis is to develop an appropriate theoretical model for treating the problem of plasma transport in a corotation dominated plasmasphere. The model presented here is intended to describe the radial transport of relatively cold plasma having an azimuthally uniform distribution in a dipolar magnetic field. The approach is conceptually similar to that of the radial diffusion model in that small scale motions are examined to infer global consequences, but the physical understanding of those small scale motions is quite different. In particular, discrete flux tubes of small cross section are assumed to move over distances large compared to their widths. The present model also differs from the corotating convection model by introducing a mechanism whereby the conservation of flux tube content along flowlines is violated. However, it is quite possible that a global convection pattern co -exists with the motions described here, leading to longitudinal asymmetries in the plasma distribution.

  10. Titan's induced magnetosphere from plasma wave, particle data and magnetometer observations

    NASA Astrophysics Data System (ADS)

    Modolo, R.; Romanelli, N.; Canu, P.; Coates, A. J.; Berthelier, J.; Bertucci, C.; Leblanc, F.; Piberne, R.; Edberg, N. J.; Kurth, W. S.; Gurnett, D. A.; Wahlund, J.

    2013-12-01

    The Magnetometer (MAG) measurements, the particle data (CAPS) are combined with the Radio and Plasma Wave Science (RPWS) observations to provide an overall and organized description of the electron plasma environment and the pickup ion distribution around Titan. RPWS observations are used to measure the electron number density of the thermal plasma close to Titan. This data set is combined with CAPS-ELS electron number density in Saturn's magnetosphere and Titan's environment. A relatively good correspondence between the number density estimated from CAPS-ELS and RPWS are most of the time observed between 0.1 - 1 cm-3. Combining both ELS and RPWS data allows deducing a continuous electron density profile going from Saturn's magnetosphere to Titan's ionosphere leading to a global electron density map in Titan's vicinity. The MAG observations are used to derive information about the ambient magnetic field environment in the vicinity of Titan and also to emphasize the bipolar tail region. Ion information such the mass composition of the plasma and ion distribution function for specific time intervals are determined from CAPS-IMS. Pick-up ions have been identified from their energy signature and mass composition for few flybys. These observations also emphasized a ring distribution, characteristic of pick-up ions. The pick-up observations, in the DRAP coordinate system, are found to be located in the +E=-vxB hemisphere as expected.

  11. The physics of thermal plasma in the magnetosphere; Proceedings of Symposium 9 of the 26th COSPAR Plenary Meeting, Toulouse, France, June 30-July 11, 1986

    NASA Technical Reports Server (NTRS)

    Chappell, C. R. (Editor); Gringauz, K. I. (Editor)

    1986-01-01

    The conference presents papers on the shape, dynamics, and thermal structure of the plasmasphere and plasmapause; the ionosphere as a supplier of plasma to the earth's magnetosphere; the modeling and remote sensing of thermal plasma in the earth's magnetosphere; and magnetospheric cold plasmas as a medium for wave generation and propagation. Particular attention is given to whistler studies of plasmasphere shape and dynamics, plasmasphere thermal structure as measured by ISEE-1 and DE-1, low-energy ion flows into the magnetosphere, field-aligned flows of ionospheric plasma in the magnetosphere, and field-aligned plasmaspheric flows at moderate latitudes. Papers are also presented on the effects of a tailward stretching geomagnetic field on the drift motion of plasma particles in the magnetospheric equatorial plane, ion cyclotron waves observed near the plasmapause, and the response of energetic particles to nightside magnetic pulsations as seen by AMPTE/CCE.

  12. Planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Stern, D. P.; Ness, N. F.

    1981-01-01

    A concise overview is presented of our understanding of planetary magnetospheres (and in particular, of that of the Earth), as of the end of 1981. Emphasis is placed on processes of astrophysical interest, e.g., on particle acceleration, collision-free shocks, particle motion, parallel electric fields, magnetic merging, substorms, and large scale plasma flows. The general morphology and topology of the Earth's magnetosphere are discussed, and important results are given about the magnetospheres of Jupiter, Saturn and Mercury, including those derived from the Voyager 1 and 2 missions and those related to Jupiter's satellite Io. About 160 references are cited, including many reviews from which additional details can be obtained.

  13. Inner Magnetospheric Superthermal Electron Transport: Photoelectron and Plasma Sheet Electron Sources

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Liemohn, M. W.; Kozyra, J. U.; Moore, T. E.

    1998-01-01

    Two time-dependent kinetic models of superthermal electron transport are combined to conduct global calculations of the nonthermal electron distribution function throughout the inner magnetosphere. It is shown that the energy range of validity for this combined model extends down to the superthermal-thermal intersection at a few eV, allowing for the calculation of the en- tire distribution function and thus an accurate heating rate to the thermal plasma. Because of the linearity of the formulas, the source terms are separated to calculate the distributions from the various populations, namely photoelectrons (PEs) and plasma sheet electrons (PSEs). These distributions are discussed in detail, examining the processes responsible for their formation in the various regions of the inner magnetosphere. It is shown that convection, corotation, and Coulomb collisions are the dominant processes in the formation of the PE distribution function and that PSEs are dominated by the interplay between the drift terms. Of note is that the PEs propagate around the nightside in a narrow channel at the edge of the plasmasphere as Coulomb collisions reduce the fluxes inside of this and convection compresses the flux tubes inward. These distributions are then recombined to show the development of the total superthermal electron distribution function in the inner magnetosphere and their influence on the thermal plasma. PEs usually dominate the dayside heating, with integral energy fluxes to the ionosphere reaching 10(exp 10) eV/sq cm/s in the plasmasphere, while heating from the PSEs typically does not exceed 10(exp 8) eV/sq cm/s. On the nightside, the inner plasmasphere is usually unheated by superthermal electrons. A feature of these combined spectra is that the distribution often has upward slopes with energy, particularly at the crossover from PE to PSE dominance, indicating that instabilities are possible.

  14. Outer magnetospheric resonances and transport: discrete and turbulent cascades in the dynamic pressure and plasma flux

    NASA Astrophysics Data System (ADS)

    Savin, Sergey; Büchner, Jörg; Zelenyi, Lev; Kronberg, Elena; Kozak, Lyudmila; Blecki, Jan; Lezhen, Liudmila; Nemecek, Zdenek; Safrankova, Jana; Skalsky, Alexander; Budaev, Vyacheslav; Amata, Ermanno

    We explore interactions of Supersonic Plasma Streams (SPS) with the Earth magnetosphere in the context of the planetary and astrophysical magnetospheres and of that of laboratory plasmas. The interactions can be inherently non-local and non-equilibrium, and even explosive due to both solar wind (SW) induced and self-generated coherent structures in the multiscale system with the scales ranging from the micro to global scales. We concentrate on the main fundamental processes arising from the SPS cascading and interactions with surface and cavity resonances in the Earth’s magnetosphere, using multi-spacecraft data (SPECTR-R, DOUBLE STAR, CLUSTER, GEOTAIL, ACE, WIND etc.). We will address the following key problems to advance our understanding of anomalous transport and boundary dynamics: - generalizations of the SPS generation mechanisms, e.g., by bow shock (BS) surface or magnetosheath (MSH) cavity resonances, triggering by interplanetary shocks, solar wind (SW) dynamic pressure jumps, foreshock nonlinear structures, etc. - the clarification of BS rippling mechanisms requires base on the relevant databases from the CLUSTER/ DOUBLE STAR/ GEOTAIL/SPECTR-R/ ACE/ WIND spacecraft, which will be used for a statistical analysis targeting the SPS statistical features as extreme events. - substantial part of the SW kinetic energy can be pumped into the BS membrane and MSH cavity modes and initiate further cascades towards higher frequencies. Accordingly we present the multipoint studies of the SPS and of related nonlinear discrete cascades (carried generally by the SPS), along with the transformation of discrete cascades of the dynamic pressure into turbulent cascades. - investigation of spectral and bi-spectral cross-correlations in SW, foreshock, MSH and in vicinity of BS and magnetopause (MP) would demonstrate that both inflow and outflow into/ from magnetosphere can be modulated by the SPS and by the related outer magnetospheric resonances as well. We demonstrate in

  15. Observation of magnetic fluctuations and rapid density decay of magnetospheric plasma in Ring Trap 1

    SciTech Connect

    Saitoh, H.; Yoshida, Z.; Morikawa, J.; Yano, Y.; Mikami, H.; Kasaoka, N.; Sakamoto, W.

    2012-06-15

    The Ring Trap 1 device, a magnetospheric configuration generated by a levitated dipole field magnet, has created high-{beta} (local {beta} {approx} 70%) plasma by using electron cyclotron resonance heating (ECH). When a large population of energetic electrons is generated at low neutral gas pressure operation, high frequency magnetic fluctuations are observed. When the fluctuations are strongly excited, rapid loss of plasma was simultaneously observed especially in a quiet decay phase after the ECH microwave power is turned off. Although the plasma is confined in a strongly inhomogeneous dipole field configuration, the frequency spectra of the fluctuations have sharp frequency peaks, implying spatially localized sources of the fluctuations. The fluctuations are stabilized by decreasing the hot electron component below approximately 40%, realizing stable high-{beta} confinement.

  16. Studies of ionospheric plasma and electrodynamics and their application to ionosphere-magnetosphere coupling

    NASA Technical Reports Server (NTRS)

    Heelis, R. A.

    1988-01-01

    The contribution of the Dynamics Explorer (DE) program to the study of small-scale structure in the equatorial ionospheric number density and the bulk motion of the plasma in the equatorial ionosphere is considered. DE results have helped elucidate the role of E region and F region winds in decreasing the magnitude of variations in the east-west plasma drift at night, as a function of magnetic flux tube apex height, with increasing height above the altitude of the peak F region concentration. Other results concern the ionospheric convection pattern at high latitudes during periods of southward IMF, the magnetosphere/solar-wind interaction that may be involved in the production of the convection pattern, and the characteristics of the high-latitude ionospheric plasma motion during periods of northward IMF.

  17. Van Allen Probe Explorations of Plasma Spatial and Temporal Scales in the Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Niehof, J. T.; Larsen, B.; Skoug, R. M.; Reeves, G. D.; MacDonald, E.; Thomsen, M.; Funsten, H. O.; Friedel, R. H.

    2013-12-01

    We utilize the variable separation of the twin satellites of the Van Allen Probes mission to explore the time and spatial stability of plasma features in the inner magnetosphere. The spacecraft are in a leader-follower configuration with an approximately nine hour orbit, but with slightly different apogees and thus periods. Exploiting the resulting variation in separations, we survey differences in the plasma environment between inbound and outbound passes from a single satellite and between the two separated in time. The time separation ranges from minutes to 4.5 hours. From the HOPE instrument we obtain pitch angle resolved measurements of the plasma environment (for electrons, protons, helium, and oxygen). By utilizing both spacecraft, temporal and spatial effects are separated. By comparing temporal variations to drift and flow times, we determine which events' evolution is adequately described by simple flow or drift and which must result from more involved physics.

  18. Examining the interaction of Europa with the Jovian magnetosphere using eruptive and multifluid plasma dynamic simulations

    NASA Astrophysics Data System (ADS)

    Paty, C. S.; Dufek, J.; Payan, A. P.

    2015-12-01

    Jupiter's icy moon Europa provides a unique laboratory for understanding the physics of moon-magnetosphere interactions. Europa possesses a conductive subsurface ocean, the interaction of which with the locally varying Jovian magnetic field is expressed by the observed inductive response. This icy moon also boasts a dynamic exosphere as well as eruptive plumes, which interact with the Jovian plasma as expressed via ultraviolet aurora. We investigate a broad range of parameter space related to the interaction of this icy moon with the rapidly rotating magnetosphere of Jupiter, systematically working through and quantifying various physical effects using a multifluid plasma dynamic modeling framework. Aside from induction and interactions with the exosphere, we will also present preliminary result from incorporating a neutral plume generated by an eruptive simulation. We run conduit simulations to get at neutral gas and particle injection velocities, which are in turn used as a source for the plasma dynamic simulations. We then investigate the distribution of neutrals, ions, and charged grains as a function of altitude.

  19. Rhea’s interaction with Saturn’s magnetosphere: Evidence for a plasma source

    NASA Astrophysics Data System (ADS)

    Jones, G. H.; Roussos, E.; Coates, A. J.; Arridge, C. S.; Kanani, S. J.; Young, D. T.; Krupp, N.; Krimigis, S. M.; Baragiola, R. A.; Berthelier, J.; Burger, M. H.; Cooper, J. F.; Crary, F. J.; Johnson, R. E.; Martens, H. R.; Reisenfeld, D. B.; Tokar, R. L.; Wilson, R. J.

    2009-12-01

    Rhea is Saturn’s second-largest moon, and orbits at 8.7 Saturn radii from the planet. The moon is continuously bombarded by magnetospheric plasma: the absorption of thermal plasma that overtakes Rhea in its orbit results in the formation of an upstream plasma wake. High energy electron dropouts - microsignatures, caused by the absorption of more energetic particles by the moon, are also observed. The unusually broad electron microsignatures observed near the moon are suggested to be evidence for the existence of a debris disk orbiting the moon (Jones et al. 2008). We present our current state of knowledge of the Rhea-magnetosphere interaction, based on data obtained by the Cassini CAPS and MIMI instruments during the spacecraft’s two closest encounters with the moon to date, on November 26, 2005, and August 30, 2007. We report on the detection of pickup ions at the moon by the CAPS instrument. This detection agrees with the results of Martens et al. (2008), who previously reported an enhancement in molecular oxygen ion distributions at the L shell of Rhea. We also summarize expectations for the upcoming close encounter on March 2, 2010.

  20. Phase A conceptual design study of the Atmospheric, Magnetospheric and Plasmas in Space (AMPS) payload

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The 12 month Phase A Conceptual Design Study of the Atmospheric, Magnetospheric and Plasmas in Space (AMPS) payload performed within the Program Development Directorate of the Marshall Space Flight Center is presented. The AMPS payload makes use of the Spacelab pressurized module and pallet, is launched by the space shuttle, and will have initial flight durations of 7 days. Scientific instruments including particle accelerators, high power transmitters, optical instruments, and chemical release devices are mounted externally on the Spacelab pallet and are controlled by the experimenters from within the pressurized module. The capability of real-time scientist interaction on-orbit with the experiment is a major characteristic of AMPS.

  1. Pulsars Magnetospheres

    NASA Technical Reports Server (NTRS)

    Timokhin, Andrey

    2012-01-01

    Current density determines the plasma flow regime. Cascades are non-stationary. ALWAYS. All flow regimes look different: multiple components (?) Return current regions should have particle accelerating zones in the outer magnetosphere: y-ray pulsars (?) Plasma oscillations in discharges: direct radio emission (?)

  2. A DE-1/whistler study of the thermal plasma structure and dynamics in the dusk bulge sector of the magnetosphere

    NASA Technical Reports Server (NTRS)

    Carpenter, D. L.

    1992-01-01

    The objective of this research was to obtain new understanding of the thermal plasma structure and dynamics of the plasmasphere bulge region of the magnetosphere, with special emphasis on the erosion process that results in a reduction in plasmasphere size and on the manner in which erosion leads to the presence of patches of dense plasma in the middle and outer afternoon-dusk magnetosphere. Case studies involving data from the DE 1, GEOS 2, and ISEE 1 satellites and from ground whistler stations Siple, Halley, and Kerguelen were used. A copy of the published paper entitled 'A case study of plasma structure in the dusk sector associated with enhanced magnetospheric convection,' is included.

  3. On the nature and statistical properties of transport barriers in magnetospheric and laboratory plasma

    NASA Astrophysics Data System (ADS)

    Savin, Sergey; Budaev, Viacheslav; Amata, Ermanno; Kozak, Liudmila; Korepanov, Valery; Buechner, Joerg; Romanov, Stanislav; Blecki, Jan; Balikhin, Mikhael; Lezhen, Liudmila

    2010-05-01

    The transport barriers near magnetospheric cusp have a dualistic feature: being very effective in limitation of the momentum transfer, they display the super-diffusive statistical properties. We show an example from Interball-1 with a rare case of extremely quiet solar wind. The inbound magnetopause crossing, being inherently turbulent in this equilibrium case, is best seen from changes of the magnetic field component signs. The ion heating starts namely in the transport barrier and proceeds deeper inward magnetosphere. It agrees with the kinetic energy transformation into the thermal one inside the barrier - the turbulent dissipation of the magnetosheath kinetic energy - as simultaneously with the ion temperature rise the general velocity component drops from its model prediction. Fitting the log-Poisson model for 1D most- dissipative structures gives qualitatively similar result. In sense of the momentum transfer the Alfvenic turbulent barrier effectively isolates the high- β part of the magnetospheric cusp, from rather fast- flowing (~ 200 km/s) magnetosheath. Contrary to that, several examples from different missions and different plasma parameters demonstrate the super-diffusive transport character. The individual Alfvenic 'collapsons' have similar scale chains to that of high kinetic pressure jets, showing mutual interaction features. We think that the interacting jets and barriers, accompanying by classic and/ or micro- reconnection, have rather general importance for the plasma physics, and for understanding of turbulence and mechanisms of magnetic field generation. These coherent, nonlinear interacting structures will be further explored in details by such missions as ROY and Cross-Scale/ SCOPE. We compare the statistical properties of transport barriers in space and fusion devices.

  4. Sputtering of Nitrogen from Titan by the interaction of Saturn's magnetospheric plasma with Titan's thermosphere

    NASA Astrophysics Data System (ADS)

    Michael, M.; Johnson, R. E.; Luhmann, J. G.

    2002-09-01

    Titan's dense, mainly molecular nitrogen atmosphere is a significant source of the neutrals in Saturn's magnetosphere. As Titan does not posses an intrinsic magnetic field, energetic Kronian magnetospheric ions may be able to penetrate Titan's atmospheric exobase and sputter atoms and molecules from the atmosphere of Titan. The sputtering of Nitrogen from Titan atmosphere by the corotating Nitrogen ions and by photodissociation had been addressed earlier (Lammer and Bauer, 1993, Shematovich et al., 2001). Penetration of pickup Nitrogen and C2H5+ ions of energy less than 1.25 keV is described here using a Monte Carlo model. The interaction of these ions with the atmospheric neutrals can lead directly or indirectly to the production of fast neutrals that collide with other atmospheric neutrals producing heating and ejection of atoms and molecules. Here results from Brecht et al (2000) are used to estimate the net flux and energy spectra of the co-rotating and pick-up ions onto the exobase while the earlier models used a simplified description of the co-rotating plasma flow onto the exobase. The relative importance of the low energy and energetic plasma particles are considered in the present study. Brecht, S.H., J.G. Luhman, and D.J. Larson, Simulation of the saturnian magnetospheric interaction, 105, 13119, 2000 Lammer, H., and S.J. Bauer, Atmospheric Mass Loss from Titan by Sputtering, Plant. Space Sci., 41, 657, 1993. Shematovich V.I., Tully C., and Johnson R.E., Suprathermal nitrogen atoms and molecules in Titan's corona, Adv. Space Res., 27, 1875, 2001.

  5. An empirical model of ion plasma in the inner magnetosphere derived from CRRES/MICS measurements

    NASA Astrophysics Data System (ADS)

    Claudepierre, S. G.; Chen, M. W.; Roeder, J. L.; Fennell, J. F.

    2016-12-01

    We describe an empirical model of energetic ion plasma (˜20-400 keV/q) that is constructed from measurements taken by the Magnetospheric Ion Composition Spectrometer (MICS) instrument that flew on the CRRES spacecraft. This is a unique data set in that it provides energetic ion composition in the near-equatorial ring current region during a very active solar maximum. The model database is binned by energy, equatorial pitch angle, L shell, and magnetic local time and provides unidirectional, differential number fluxes of the major ionic constituents of the inner magnetosphere, such as protons (H+), singly charged oxygen (O+), and singly charged helium (He+). The H+ and O+ model fluxes are examined in detail and are consistent with well-known particle transport effects (e.g., adiabatic heating). We also validate these model fluxes against a number of other ion plasma models that are available in the literature. The primary finding is the elevated levels of energetic O+ flux during the CRRES era. We attribute this to a solar cycle effect, related to the enhanced upwelling and oxygen outflow from the ionosphere that occurs during solar maximum, driven by elevated solar extreme ultraviolet radiation. We briefly discuss the implications that the enhanced O+ environment during the CRRES era may have for other results derived from CRRES observations (e.g., statistical wave distributions).

  6. Magnetospheric plasma analyzer - Initial three-spacecraft observations from geosynchronous orbit

    NASA Astrophysics Data System (ADS)

    McComas, D. J.; Bame, S. J.; Barraclough, B. L.; Donart, J. R.; Elphic, R. C.; Gosling, J. T.; Moldwin, M. B.; Moore, K. R.; Thomsen, M. F.

    1993-08-01

    A synoptic view of the morphology of the magnetosphere at geosynchronous orbit over a 6-wk interval in early 1992 is synthesized on the basis of simultaneous observations from three longitudinally separated spacecraft. Seven regions with characteristic plasma populations were discovered during this period. It is found that at geomagnetically quiet times geosynchronous orbit can lie entirely within the plasmasphere, while at more active times only the afternoon to evening portions of the orbit are typically within the plasmasphere. The plasma convection inside the plasmasphere is found to be generally sunward in the corotating reference frame, independent of activity level, in contrast to previous studies. Simultaneous prenoon and postnoon observations show that the magnetopause shape can be highly asymmetric about the earth-sun line.

  7. The evolution of high-temperature plasma in magnetar magnetospheres and its implications for giant flares

    SciTech Connect

    Takamoto, Makoto; Kisaka, Shota; Suzuki, Takeru K.; Terasawa, Toshio E-mail: kisaka@post.kek.jp E-mail: terasawa@icrr.u-tokyo.ac.jp

    2014-05-20

    In this paper we propose a new mechanism describing the initial spike of giant flares in the framework of the starquake model. We investigate the evolution of a plasma on a closed magnetic flux tube in the magnetosphere of a magnetar in the case of a sudden energy release, and discuss the relationship with observations of giant flares. We perform one-dimensional, numerical simulations of the relativistic magnetohydrodynamics in Schwarzschild geometry. We assume energy is injected at the footpoints of the loop by a hot star surface containing random perturbations of the transverse velocity. Alfvén waves are generated and propagate upward, accompanying very hot plasma which is also continuously heated by nonlinearly generated compressive waves. We find that the front edges of the fireball regions collide at the top of the tube with their symmetrically launched counterparts. This collision results in an energy release that can describe the light curve of the initial spikes of giant flares.

  8. Seasonal variation and dynamics of Saturn's magnetospheric plasma, after 8 years of Cassini in orbit.

    NASA Astrophysics Data System (ADS)

    Sergis, N.

    2012-12-01

    Saturn orbits the Sun with a period of nearly 29.5 years and has an obliquity of 26.73°. As a result, Saturn presents seasonal variations similar to Earth's, but with much longer seasons, as the tilt between the planet's spin axis and the solar wind vary (approximately sinusoidally) with time between solstices. Saturn was close to its equinox (tilt below 8.1°) during the Pioneer 11 and Voyager 1 and 2 flybys that took place between September 1979 and August 1981, so any seasonal effects would have been relatively hard to see in the limited data from these missions. More than 2 decades later, on July 4, 2004, Cassini began orbiting Saturn, returning a variety of in situ and remote measurements. During the last 8 years, Cassini covered a large part of the Saturnian system and offered the opportunity of sampling the planetary magnetosphere not just at different seasons, but also at seasonal phases that are symmetric to the Saturnian equinox (August 2009). In this talk, we focus on the seasonal effects seen in the magnetosphere of Saturn as the angle between the solar wind flow and the Saturn-Sun direction changes from +23.7° (northern hemisphere winter) at the arrival of Cassini, to -14.9° (northern hemisphere summer) on July 2012. Particle and magnetic field data taken from a extensive set of equatorial and high latitude orbits of Cassini, at various distances and local times, show that: (a) the plasma sheet of Saturn has the form of a magnetodisk, with an energy-dependent vertical structure, being thicker by a factor of ~2 in the energetic particle range than in the electron plasma, and (b) it exhibits intense dynamical behavior, evident in in-situ particle measurements but also in energetic neutral atom (ENA) emissions. The study of the pre-equinox high latitude orbits revealed that the night side plasma sheet was tilted northward beyond a radial distance of ~15 Rs (1Rs=60,258 km). As equinox approached, Cassini observed a clear decrease in the tilt of the

  9. Simulation of Mini-Magnetospheric Plasma Propulsion (M2P2) Interacting with an External Plasma Wind

    NASA Technical Reports Server (NTRS)

    Winglee, R. M.; Euripides, P.; Ziemba, T.; Slough, J.; Giersch, L.

    2003-01-01

    Substantial progress has been made over the last year in the development of the laboratory Mini-Magnetospheric Plasma Propulsion (M2P2) prototype. The laboratory testing has shown that that the plasma can be produced at high neutral gas efficiency, at high temperatures (a few tens of eV) with excellent confinement up to the point where chamber wall interactions dominate the physics. This paper investigates the performance of the prototype as it is opposed by an external plasma acting as a surrogate for the solar wind. The experiments were performed in 5ft diameter by 6ft long vacuum chamber at the University of Washington. The solar wind source comprised of a 33 kWe arc jet attached to a 200 kWe inductively generated plasma source. The dual plasma sources allow the interaction to be studied for different power levels, shot duration and production method. It is shown that plasma from the solar wind source (SWS) is able to penetrate the field of the M2P2 magnetic when no plasma is present. With operation of the M2P2 plasma source at only 1.5 kWe, the penetration of the SWS even at the highest power of operation at 200 kWe is stopped. This deflection is shown to be greatly enhanced over that produced by the magnet alone. In addition it is shown that with the presence of the SWS, M2P2 is able to produce enhanced magnetized plasma production out to at least 10 magnet radii where the field strength is only marginally greater than the terrestrial field. The results are consistent with the initial predictions that kWe M2P2 systems would be able to deflect several hundred kWe plasma winds to produce enhanced propulsion for a spacecraft.

  10. Kinetic models for space plasmas: Recent progress for the solar wind and the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Pierrard, V.; Moschou, S. P.; Lazar, M.; Borremans, K.; Rosson, G. Lopez

    2016-11-01

    Recent models for the solar wind and the inner magnetosphere have been developed using the kinetic approach. The solution of the evolution equation is used to determine the velocity distribution function of the particles and their moments. The solutions depend on the approximations and assumptions made in the development of the models. Effects of suprathermal particles often observed in space plasmas are taken into account to show their influence on the characteristics of the plasma, with specific applications for coronal heating and solar wind acceleration. We describe in particular the results obtained with the collisionless exospheric approximation based on the Lorentzian velocity distribution function for the electrons and its recent progress in three dimensions. The effects of Coulomb collisions obtained by using a Fokker-Planck term in the evolution equation were also investigated, as well as effects of the whistler wave turbulence at electron scale and the kinetic Alfven waves at the proton scale. For solar wind especially, modelling efforts with both magnetohydrodynamic and kinetic treatments have been compared and combined in order to improve the predictions in the vicinity of the Earth. Photospheric magnetograms serve as observational input in semi-empirical coronal models used for estimating the plasma characteristics up to coronal heliocentric distances taken as boundary conditions in solar wind models. The solar wind fluctuations may influence the dynamics of the space environment of the Earth and generate geomagnetic storms. In the magnetosphere of the Earth, the trajectories of the particles are simulated to study the plasmasphere, the extension of the ionosphere along closed magnetic field lines and to better understand the physical mechanisms involved in the radiation belts dynamics.

  11. Laser experiments to simulate coronal mass ejection driven magnetospheres and astrophysical plasma winds on compact magnetized stars

    NASA Astrophysics Data System (ADS)

    Horton, W.; Ditmire, T.; Zakharov, Yu. P.

    2010-06-01

    Laboratory experiments using a plasma wind generated by laser-target interaction are proposed to investigate the creation of a shock in front of the magnetosphere and the dynamo mechanism for creating plasma currents and voltages. Preliminary experiments are shown where measurements of the electron density gradients surrounding the obstacles are recorded to infer the plasma winds. The proposed experiments are relevant to understanding the electron acceleration mechanisms taking place in shock-driven magnetic dipole confined plasmas surrounding compact magnetized stars and planets. Exploratory experiments have been published [P. Brady, T. Ditmire, W. Horton, et al., Phys. Plasmas 16, 043112 (2009)] with the one Joule Yoga laser and centimeter sized permanent magnets.

  12. Global Time Variability in the Thermal Plasma Composition of the Saturnian Magnetosphere

    NASA Astrophysics Data System (ADS)

    Ip, W.

    2013-12-01

    The Saturnian magnetosphere is characterized by strong coupling between the charged particles and the neutral gas cloud emitted from Enceladus and the rings. Besides the mass-loading effect due to ionization of the water-group gas, the charge transfer process leading to the generation of energetic neutral atoms is a key process of particle loss and atmospheric precipitation. Detailed measurements by the plasma instruments like CAPS and MIMI have provided many insights to the magnetospheric composition and dynamics driven by such plasma-gas interaction. For example, a statistical study of the CAPS measurements by Thomsen et al. (2010) has shown the relative abundances and radial profiles of different ion species in the corotating thermal plasma disc. Another interesting result has to do with the seasonal variability of the suprathermal O2+ molecular ions detected by the CHEMS/MIMI experiment (Christon et al., 2013) which might have to do with the extended oxygen atmosphere of the ring system (Tseng et al., 2010). In this work, we will use a time-dependent radial diffusion transport model coupled with ion chemistry calculation (Ip, 2000) to simulate the global distributions of various ions (H+, H2+, O+, OH+, H2O+, H3O+, and O2+ )between the outer edge of the A ring to the orbit of Titan. Our parametric study will examine how the thermal ion composition of the Saturnian magnetosphere would be affected by solar cycle effect, seasonal variation of the ring atmosphere, and the suprathermal electron flux. Christon, S.P., Hamilton, D.C., DiFabio, R.D., Mitchell, D.G., Krimigis, S.M., and Jontof-Hutter, D.S., J. Geophys. Res., 118, 3446-3462, 2013. Ip, W.-H., Planet. Space Sci., 48, 775-783, 2000. Thomsen, M.F., Reisenfeld, D.B., Delapp, D.M., Tokar, R.C., Young, D.T., Crary, F.J., Sittler, E.C., McGraw, M.A., and Williams, J.D., J. Geophys. Res., 115, A10220, 2010. Tseng, W.-L., Ip, W.-H., Johnson, R.E., Cassidy, T.A., and Elrod, M.K., Icarus, 206, 382-389, 2010.

  13. Energy and Mass Transport of Magnetospheric Plasmas during the November 2003 Magnetic Storm

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Chging; Moore, Thomas

    2008-01-01

    Intensive energy and mass transport from the solar wind across the magnetosphere boundary is a trigger of magnetic storms. The storm on 20-21 November 2003 was elicited by a high-speed solar wind and strong southward component of interplanetary magnetic field. This storm attained a minimum Dst of -422 nT. During the storm, some of the solar wind particles enter the magnetosphere and eventually become part of the ring current. At the same time, the fierce solar wind powers strong outflow of H+ and O+ from the ionosphere, as well as from the plasmasphere. We examine the contribution of plasmas from the solar wind, ionosphere and plasmasphere to the storm-time ring current. Our simulation shows, for this particular storm, ionospheric O+ and solar wind ions are the major sources of the ring current particles. The polar wind and plasmaspheric H+ have only minor impacts. In the storm main phase, the strong penetration of solar wind electric field pushes ions from the geosynchronous orbit to L shells of 2 and below. Ring current is greatly intensified during the earthward transport and produces a large magnetic depression in the surface field. When the convection subsides, the deep penetrating ions experience strong charge exchange loss, causing rapid decay of the ring current and fast initial storm recovery. Our simulation reproduces very well the storm development indicated by the Dst index.

  14. Inner magnetosphere plasma, statistics from the Van Allen Probes HOPE instrument and data release 3.

    NASA Astrophysics Data System (ADS)

    Larsen, B.; Skoug, R. M.; Olson, D. K.; Reeves, G.; Friedel, R. H.; Funsten, H. O.

    2015-12-01

    As the twin Van Allen probes spacecraft complete three years on-orbit more than a complete revolution in local time has occurred. We present the state of the HOPE plasma data and statistics of the plasma distribution inside of geostationary orbit. Over the course of the mission a better understanding of the instrument has been gained and the needed corrections added to the data to enable long-term statistics to be collected and compared with confidence. The major correction to the data is the expected degradation of the channel electron multiplier (CEM) efficiency as a function of time and count rate. HOPE provides background data sufficient to monitor the absolute detection efficiency throughout the mission. We have incorporated a time dependent gain correction factor to the data that normalizes the gain and thus the derived plasma properties. In addition the CEM bias voltage was adjusted bringing the gain back toward launch values. With a standard set of data electron and ion composition statistics are computed and presented. These statistics serve as a L-MLT dependent distribution to begin inner magnetosphere plasma modeling, instrument comparison, and climatology studies. These data are presented as ECT HOPE release 3.

  15. Inner magnetosphere plasma, statistics from the Van Allen Probes HOPE instrument and data release 3.

    NASA Astrophysics Data System (ADS)

    Lotko, W.; Smith, R. H.; Zhang, B.; Ouellette, J.; Brambles, O.; Lyon, J.; Wiltberger, M. J.

    2014-12-01

    As the twin Van Allen probes spacecraft complete three years on-orbit more than a complete revolution in local time has occurred. We present the state of the HOPE plasma data and statistics of the plasma distribution inside of geostationary orbit. Over the course of the mission a better understanding of the instrument has been gained and the needed corrections added to the data to enable long-term statistics to be collected and compared with confidence. The major correction to the data is the expected degradation of the channel electron multiplier (CEM) efficiency as a function of time and count rate. HOPE provides background data sufficient to monitor the absolute detection efficiency throughout the mission. We have incorporated a time dependent gain correction factor to the data that normalizes the gain and thus the derived plasma properties. In addition the CEM bias voltage was adjusted bringing the gain back toward launch values. With a standard set of data electron and ion composition statistics are computed and presented. These statistics serve as a L-MLT dependent distribution to begin inner magnetosphere plasma modeling, instrument comparison, and climatology studies. These data are presented as ECT HOPE release 3.

  16. On the adiabatic walking of plasma waves in a pulsar magnetosphere

    SciTech Connect

    Melikidze, George I.; Gil, Janusz; Mitra, Dipanjan E-mail: jag@astro.ia.uz.zgora.pl

    2014-10-20

    The pulsar radio emission is generated in the near magnetosphere of the neutron star, and it must propagate through the rest of it to emerge into the interstellar medium. An important issue is whether this propagation affects the planes of polarization of the generated radiation. Observationally, there is sufficient evidence that the emerging radiation is polarized parallel or perpendicular to the magnetic field line planes that should be associated with the ordinary (O) and extraordinary (X) plasma modes, respectively, excited by some radiative process. This strongly suggests that the excited X and O modes are not affected by the so-called adiabatic walking that causes a slow rotation of polarization vectors. In this paper, we demonstrate that the conditions for adiabatic walking are not fulfilled within the soliton model of pulsar radio emission, in which the coherent curvature radiation occurs at frequencies much lower than the characteristic plasma frequency, The X mode propagates freely and observationally represents the primary polarization mode. The O mode has difficulty escaping from the pulsar plasma; however, it is sporadically observed as a weaker secondary polarization mode. We discuss a possible scenario under which the O mode can also escape from the plasma and reach an observer.

  17. Magnetohydrodynamic Model of Europa's Interaction with Jupiter's Magnetosphere: Influence of Plumes in Europa's Atmosphere on the Plasma Environment

    NASA Astrophysics Data System (ADS)

    Bloecker, A.; Saur, J.; Roth, L.; Hartkorn, O. A.

    2014-12-01

    We develop a three-dimensional magnetohydrodynamic (MHD) model to study the influence of plumes in Europa's atmosphere on the interaction with Jupiter's magnetosphere and plasma environment. We consider the cases when Europa is located in, above and below the magnetospheric current sheet. Recently, Roth et al. (2014) discovered transient water vapor plumes near Europa's south pole. Here we provide a structured study of the influence of plumes in Europa's atmosphere on the local plasma interaction and the Alfvén wings. In our model we have included an asymmetric atmosphere of Europa, the electromagnetic induction in a subsurface water ocean, the plasma production and loss due to electron impact ionization and dissociative recombination. Additionally, our model takes into account different types of model plumes at the south pole. Our analysis suggests that the plume modifies the global plasma interaction of Europa. The strength of the modification depends on the physical properties of the plume.

  18. Comment on "Mode Conversion of Waves In The Ion-Cyclotron Frequency Range in Magnetospheric Plasmas"

    SciTech Connect

    Kim, Eun; Johnson, J. R.

    2014-02-01

    Recently, Kazakov and Fulop [1] studied mode conversion (MC) at the ion-ion hybrid (IIH) resonance in planetary magnetospheric plasmas by simplifying the dispersion relation of the fast wave (FW) modes to describe a cutoff-resonance (CR) pair near the IIH resonance, which can be reduced to a Budden problem. They suggested that when the IIH resonance frequency (ωS) approaches the crossover frequency (ωcr), and the parallel wavenumber (k∥) is close to the critical wavenumber k* ∥(ωS = ωcr), MC can be efficient for arbitrary heavy ion density ratios. In this Comment, we argue that (a) the FW dispersion relation cannot be simplified to the CR pair especially near ωcr because in many parameter regimes there is a cutoff-resonance-cutoff (CRC) triplet that completely changes the wave absorption; and (b) the maximum MC efficiency does not always occur near k∥ ≈ k*∥∥.

  19. Multifluid MHD simulation of Saturn's magnetosphere: Dynamics of mass- and momentum-loading, and seasonal variation of the plasma sheet

    NASA Astrophysics Data System (ADS)

    Rajendar, A.; Paty, C. S.; Arridge, C. S.; Jackman, C. M.; Smith, H. T.

    2013-12-01

    Saturn's magnetosphere is driven externally, by the solar wind, and internally, by the planet's strong magnetic field, rapid rotation rate, and the addition of new plasma created from Saturn's neutral cloud. Externally, the alignment of the rotational and magnetic dipole axes, combined with Saturn's substantial inclination to its plane of orbit result in substantial curvature of the plasma sheet during solstice. Internally, new water group ions are produced in the inner regions of the magnetosphere from photoionization and electron-impact ionization of the water vapor and OH cloud sourced from Enceladus and other icy bodies in Saturn's planetary system. In addition to this, charge-exchange collisions between the relatively fast-moving water group ions and the slower neutrals results in a net loss of momentum from the plasma. In order to study these phenomena, we have made significant modifications to the Saturn multifluid model. This model has been previously used to investigate the external triggering of plasmoids and the interchange process using a fixed internal source rate. In order to improve the fidelity of the model, we have incorporated a physical source of mass- and momentum-loading by including an empirical representation of Saturn's neutral cloud and modifying the multifluid MHD equations to include mass- and momentum-loading terms. Collision cross-sections between ions, electrons, and neutrals are calculated as functions of closure velocity and energy at each grid point and time step, enabling us to simulate the spatially and temporally varying plasma-neutral interactions. In addition to this, by altering the angle of incidence of the solar wind relative to Saturn's rotational axis and applying a realistic latitudinally- and seasonally-varying ionospheric conductivity, we are also able to study seasonal effects on Saturn's magnetosphere. We use the updated multifluid simulation to investigate the dynamics of Saturn's magnetosphere, focusing specifically

  20. Two Dual Ion Spectrometer Flight Units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS)

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi

    2014-01-01

    Two Dual Ion Spectrometer flight units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS) have returned to MSFC for flight testing. Anticipated to begin on June 30, tests will ensue in the Low Energy Electron and Ion Facility of the Heliophysics and Planetary Science Office (ZP13), managed by Dr. Victoria Coffey of the Natural Environments Branch of the Engineering Directorate (EV44). The MMS mission consists of four identical spacecraft, whose purpose is to study magnetic reconnection in the boundary regions of Earth's magnetosphere.

  1. Modeling the seasonal variability of the plasma environment in Saturn's magnetosphere between main rings and Mimas

    NASA Astrophysics Data System (ADS)

    Tseng, W.-L.; Johnson, R. E.; Elrod, M. K.

    2013-03-01

    The detection of O2+ and O+ ions over Saturn's main rings by the Cassini INMS and CAPS instruments at Saturn orbit insertion (SOI) in 2004 confirmed the existence of the ring atmosphere and ionosphere. The source mechanism was suggested to be primarily photolytic decomposition of water ice producing neutral O2 and H2 (Johnson et al., 2006). Therefore, we predicted that there would be seasonal variations in the ring atmosphere and ionosphere due to the orientation of the ring plane to the sun (Tseng et al., 2010). The atoms and molecules scattered out of the ring atmosphere by ion-molecule collisions are an important source for the inner magnetosphere (Johnson et al., 2006; Martens et al., 2008; Tseng et al., 2010, 2011). This source competes with water products from the Enceladus' plumes, which, although possibly variable, do not appear to have a seasonal variability (Smith et al., 2010). Recently, we found that the plasma density, composition and temperature in the region from 2.5 to 3.5 RS exhibited significant seasonal variation between 2004 and 2010 (Elrod et al., submitted for publication). Here we present a one-box ion chemistry model to explain the complex and highly variable plasma environment observed by the CAPS instrument on Cassini. We combine the water products from Enceladus with the molecules scattered from a corrected ring atmosphere, in order to describe the temporal changes in ion densities, composition and temperature detected by CAPS. We found that the observed temporal variations are primarily seasonal, due to the predicted seasonal variation in the ring atmosphere, and are consistent with a compressed magnetosphere at SOI.

  2. Plasma pressure in Mercury's equatorial magnetosphere derived from MESSENGER Magnetometer observations

    NASA Astrophysics Data System (ADS)

    Korth, Haje; Anderson, Brian J.; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Johnson, Catherine L.; Purucker, Michael E.; Winslow, Reka M.; Solomon, Sean C.; McNutt, Ralph L., Jr.

    2011-11-01

    Since insertion of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft into orbit around Mercury on 18 March 2011, the probe's Magnetometer has routinely observed localized reductions of the magnetic field magnitude below the level predicted by a planetary dipole model corrected for magnetospheric magnetic fields. These magnetic depressions are observed on almost every orbit, and the latitude at which they are observed is local-time dependent. The depression signatures are indicators of the presence of enhanced plasma pressures, which inflate the magnetic field locally to maintain pressure balance, thus lowering the magnetic flux density. Mapping the magnetic depressions in local time and latitude provides insight into the plasma distribution near the planet, which complements that provided by MESSENGER's Fast Imaging Plasma Spectrometer. The spatial distribution shows that magnetic depressions are concentrated in two distinct regions, one near the equator on the nightside and another at high latitudes principally on the dayside. Here we focus on the nightside, equatorial pressure signatures, which we attribute to the magnetotail plasma sheet. The plasma-sheet pressures extend from dusk to dawn and are offset northward from the planetary geographic equator by about 10° in latitude, commensurate with the offset of the planetary dipole. The pressures associated with the plasma-sheet depressions range from 0.1 to 3 nPa and are systematically higher at dawn than at dusk. Proton gradient-curvature and convection drift in Mercury's dipole magnetic field with a dawn-to-dusk electric field result in low drift velocities near dawn, leading to systematically higher densities and pressures at dawn than at dusk, consistent with the observations.

  3. Quantifying the Role of Different Magnetospheric Plasma Waves in Diffuse Auroral Precipitation

    NASA Astrophysics Data System (ADS)

    Thorne, R. M.; Ni, B.; Li, W.; Zhang, X.; Bortnik, J.

    2015-12-01

    Diffuse auroral pecipitation provides a major source of ionization for the high latitude upper atmosphere, and as such controls the spatial distribution of ionospheric conductivity and its variability during geomagnetic activity. The physical mechanisms responsible for diffuse auroral precipitation have been debated for several decades. But recent detailed modeling of the rates of electron scattering by plasma waves, together with new and improved observations of the wave and particle environment in space, have allowed us to identify the dominant mechanisms responsible for the precipitation of plasma sheet electrons into the atmosphere. At lower invariant latitude (L< 8) a combination of lower and upper band chorus emissions provides the dominant scattering mechanism and can also account for the unique anisotropic pitch angle distribution left in space, which can continue to provide the source for chorus excitation over the dawn side of the magnetosphere. However, at higher L shells the electron anisotropy is insufficient to cause chorus excitation, but the residual loss cone distribution can excite electrostatic cyclotron harmonic (ECH) waves, which are the dominant scattering agent at higher invariant latitude. Both chorus and ECH waves are capable of causing electron scattering at the strong diffusion rate during more intense geomagnetic activity, and this can lead to a significant reduction of plasma sheet electron flux able to reach the dayside, which acconts fore the strong day-night asymmetry of diffuse auroral precipitation.

  4. Spacecraft plume interactions with the magnetosphere plasma environment in geostationary Earth orbit

    NASA Astrophysics Data System (ADS)

    Stephani, K. A.; Boyd, I. D.

    2016-02-01

    Particle-based kinetic simulations of steady and unsteady hydrazine chemical rocket plumes are presented in a study of plume interactions with the ambient magnetosphere in geostationary Earth orbit. The hydrazine chemical rocket plume expands into a near-vacuum plasma environment, requiring the use of a combined direct simulation Monte Carlo/particle-in-cell methodology for the rarefied plasma conditions. Detailed total and differential cross sections are employed to characterize the charge exchange reactions between the neutral hydrazine plume mixture and the ambient hydrogen ions, and ion production is also modeled for photoionization processes. These ionization processes lead to an increase in local plasma density surrounding the spacecraft owing to a partial ionization of the relatively high-density hydrazine plume. Results from the steady plume simulations indicate that the formation of the hydrazine ion plume are driven by several competing mechanisms, including (1) local depletion and (2) replenishing of ambient H+ ions by charge exchange and thermal motion of 1 keV H+ from the ambient reservoir, respectively, and (3) photoionization processes. The self-consistent electrostatic field forces and the geostationary magnetic field have only a small influence on the dynamics of the ion plume. The unsteady plume simulations show a variation in neutral and ion plume dissipation times consistent with the variation in relative diffusion rates of the chemical species, with full H2 dissipation (below the ambient number density levels) approximately 33 s after a 2 s thruster burn.

  5. Response of Jupiter's inner magnetosphere to the solar wind derived from extreme ultraviolet monitoring of the Io plasma torus

    NASA Astrophysics Data System (ADS)

    Murakami, Go; Yoshioka, Kazuo; Yamazaki, Atsushi; Tsuchiya, Fuminori; Kimura, Tomoki; Tao, Chihiro; Kita, Hajime; Kagitani, Masato; Sakanoi, Takeshi; Uemizu, Kazunori; Kasaba, Yasumasa; Yoshikawa, Ichiro; Fujimoto, Masaki

    2016-12-01

    Because Jupiter's magnetosphere is huge and is rotationally dominated, solar wind influence on its inner part has been thought to be negligible. Meanwhile, dawn-dusk asymmetric features of this region have been reported. Presence of dawn-to-dusk electric field is one of the leading explanations of the asymmetry; however, the physical process of generating such an intense electric field still remains unclear. Here we present long and continuous monitoring of the extreme ultraviolet emissions from the Io plasma torus in Jupiter's inner magnetosphere made by the Hisaki satellite between December 2013 and March 2014. We found five occasions where the dusk/dawn brightness ratio was enhanced above 2.5 in response to rapid increase of the solar wind dynamic pressure. The enhancement is achieved as the dusk region brightens and the dawn region dims. The observation indicates that dawn-to-dusk electric field in the inner magnetosphere is enhanced under compressed conditions.

  6. Properties of hot electrons in the Jovian inner magnetosphere deduced from extended observations of the Io Plasma Torus

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Ichiro; Yoshioka, Kazuo; Murakami, Go; Suzuki, Fumiharu; Hikida, Reina; Yamazaki, Atsushi; Kimura, Tomoki; Tsuchiya, Fuminori; Kagitani, Masato; Sakanoi, Takeshi; Uemizu, Kazunori; Tao, Chihiro; Nozawa, Hiromasa; Kasaba, Yasumasa; Fujimoto, Masaki

    2016-11-01

    One of the focal points of interest in Jovian magnetospheric physics is the transport of energy and particles into the inner region. While an explosive energy release event in the midmagnetosphere is manifested as an aurora transient, its connection to the inner part has not been investigated due to sparsity of observations. Here we take the advantage of long-term and quasi-continuous simultaneous monitoring of the polar aurora and the Io Plasma Torus (IPT) located in the inner magnetosphere by Extreme Ultraviolet Spectroscope for Exospheric Dynamics/Hisaki. Studies on temporal characteristics over hours enable us to see slow ( 10 h) coupling between the middle and inner magnetosphere as well as to quantify the temperature of hot electrons in the IPT. We derive parameters that characterize the strong particle acceleration process.

  7. Measurement of RF electric field in high- β plasma using a Pockels detector in magnetosphere plasma confinement device RT-1

    NASA Astrophysics Data System (ADS)

    Mushiake, Toshiki; Nishiura, M.; Yoshida, Z.; Yano, Y.; Kawazura, Y.; Saitoh, H.; Yamasaki, M.; Kashyap, A.; Takahashi, N.; Nakatsuka, M.; Fukuyama, Atsushi

    2015-11-01

    The magnetosphere plasma confinement device RT-1 generates a dipole magnetic field that can confine high- β plasma by using a levitated superconducting coil. So far it is reported that high temperature electrons (up to 50keV) exist and that the local electron βe value exceeds more than 100%. However, the ion β value βi remains low in the present high- β state. To realize a high-βi state, we have started Ion Cyclotron Heating (ICH) experiments. For efficient ICH in a dipole topology, it is important to measure RF electric fields and characterize the propagation of RF waves in plasmas. On this viewpoint, we started direct measurement of local RF electric fields in RT-1 with a Pockels sensor system. A non-linear optical crystal in the Pockels sensor produces birefringence in an ambient electric field. The refractive index change of the birefringence is proportional to the applied electric field strength, which can be used to measure local electric fields. RF electric field distribution radiated from an ICH antenna was measured inside RT-1 in air, and was compared with numerical results calculated by TASK code. Results on the measurement of electric field distribution in high- β plasma and evaluation of the absorbed RF power into ions will be reported. Supported by JSPS KAKENHI Grant Numbers 23224014.

  8. Empirical probability model of cold plasma environment in the Jovian magnetosphere

    NASA Astrophysics Data System (ADS)

    Futaana, Yoshifumi; Wang, Xiao-Dong; Barabash, Stas; Roussos, Elias; Truscott, Pete

    2015-04-01

    We analyzed the Galileo PLS dataset to produce a new cold plasma environment model for the Jovian magneto- sphere. Although there exist many sophisticated radiation models, treating energetic plasma (e.g. JOSE, GIRE, or Salammbo), only a limited number of simple models has been utilized for cold plasma environment. By extend- ing the existing cold plasma models toward the probability domain, we can predict the extreme periods of Jovian environment by specifying the percentile of the environmental parameters. The new model was produced in the following procedure. We first referred to the existing cold plasma models of Divine and Garrett, 1983 (DG83) or Bagenal and Delamere 2011 (BD11). These models are scaled to fit the statistical median of the parameters obtained from Galileo PLS data. The scaled model (also called as "mean model") indicates the median environment of Jovian magnetosphere. Then, assuming that the deviations in the Galileo PLS parameters are purely due to variations in the environment, we extended the mean model toward the percentile domain. The input parameter of the model is simply the position of the spacecraft (distance, magnetic longitude and lati- tude) and the specific percentile (e.g. 0.5 for the mean model). All the parameters in the model are described in mathematical forms; therefore the needed computational resources are quite low. The new model can be used for assessing the JUICE mission profile. The spatial extent of the model covers the main phase of the JUICE mission; namely from the Europa orbit to 40 Rj (where Rj is the radius of Jupiter). In addition, theoretical extensions toward the latitudinal direction are also included in the model to support the high latitude orbit of the JUICE spacecraft.

  9. Calculation of Magnetospheric Equilibria and Evolution of Plasma Bubbles with a New Finite-Volume MHD/Magnetofriction Code

    NASA Astrophysics Data System (ADS)

    Silin, I.; Toffoletto, F.; Wolf, R.; Sazykin, S. Y.

    2013-12-01

    We present a finite-volume MHD code for simulations of magnetospheric dynamics of the plasma sheet and the inner magnetosphere. The code uses staggered non-uniform Cartesian grids to preserve the divergence-free magnetic fields, along with various numerical approximations and flux limiters for the plasma variables. The code can be initialized with empirical magnetic field models, such as the Tsyganenko models along with pressure information from either the Tsyganenko-Mukai models, or observational data, such as DMSP pressure maps. Artificial "friction term" can be added to the momentum equation, which turns the MHD code into "magnetofriction" code which can be used to construct approximate equilibrium solutions. We demonstrate some applications for our code, in both the "magnetofriction" and MHD mode, including relaxation of the empirical models to equilibrium and the evolution of a plasma bubble in the near magnetotail. The latter MHD simulation results exhibit oscillations about their equilibrium position in agreement with recent observations.

  10. Magnetospheric convection at Uranus

    NASA Technical Reports Server (NTRS)

    Selesnick, R. S.

    1987-01-01

    The unusual configuration of the Uranian magnetosphere leads to differences in the relative effects of solar wind induced magnetospheric convection and plasma corotation from those at the other planets. At the present epoch the orientation of the rotation axis of Uranus with respect to the solar wind flow direction leads to a decoupling of the convective and corotational flows, allowing plasma from the tail to move unimpeded through the inner magnetosphere. As Uranus progresses in its orbit around the sun, corotation plays a gradually more important role and the plasma residence times within the magnetosphere increase. When the rotation axis finally becomes perpendicular to the solar wind flow, corotation is dominant.

  11. Magnetospheric Plasma Studies Using Data from the Dynamics High and Low Altitude Plasma Instruments.

    DTIC Science & Technology

    1983-05-15

    the research reported here was Dy- namics Explorer 1 (DE-1). The DE-1 High Altitude Plasma Instrument (HAPI) consists of five electrostatic analyzers...paper (Lin et al, 1983). The High Altitude Plasma Instrument (HAPI) on Dynamics Explorer 1 (DE-1) made differential flux measurements of electrons and...N. Eaker, W. C. Gibson, and R. A. Hoffman, High Altitude Plasma Instrument for Dynamics Explorer-A, Space Sci. Instrum., 5, 455, 1981. Burch, J. L

  12. Magnetospheric Plasma Studies Using Data from the Dynamics High and Low Altitude Plasma Instruments.

    DTIC Science & Technology

    1984-05-15

    High Altitude Plasma Instrument (HAPI) [Burch et al, 1981] on DE-1 are shown...Accreeration Regions, J. Geophys. Res. , 84, 5863, 1979. Burch, J. L., J. D. Winningham, V. A. Blevins, N. Eaker, W. C. Gibson, and R. A. Hoffman, High - altitude plasma instrument for... Altitude Plasma Instrument (HAPI) consists of five elec- trostatic analyzers mounted in a fan-shaped angular array at angles of 450, 780, 900, 1020,

  13. The magnetospheres of the outer planets

    SciTech Connect

    Mcnutt, R.L., Jr. )

    1991-01-01

    Research on the magnetospheres of all of the outer planets including Jupiter, Uranus, Neptune, and Pluto is reviewed for the 1987-1990 time period. Particular attention is given to magnetospheric structure, plasma transport, Jovian aurora, Io and the plasma torus, Titan and its magnetospheric interactions, rings and dusty plasmas, magnetospheric convection, and satellite interactions.

  14. Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, J. A.

    1999-01-01

    Among the major discoveries made by the Mariner 10 mission to the inner planets was the existence of an intrinsic magnetic field at Mercury with a dipole moment of approx. 300 nT R(sup 3, sub M). This magnetic field is sufficient to stand off the solar wind at an altitude of about 1 R(sub M) (i.e. approx. 2439 km). Hence, Mercury possesses a 'magnetosphere' from which the so]ar wind plasma is largely excluded and within which the motion of charged particles is controlled by the planetary magnetic field. Despite its small size relative to the magnetospheres of the other planets, a Mercury orbiter mission is a high priority for the space physics community. The primary reason for this great interest is that Mercury unlike all the other planets visited thus far, lacks a significant atmosphere; only a vestigial exosphere is present. This results in a unique situation where the magnetosphere interacts directly with the outer layer of the planetary crust (i.e. the regolith). At all of the other planets the topmost regions of their atmospheres become ionized by solar radiation to form ionospheres. These planetary ionospheres then couple to electrodynamically to their magnetospheres or, in the case of the weakly magnetized Venus and Mars, directly to the solar wind. This magnetosphere-ionosphere coupling is mediated largely through field-aligned currents (FACs) flowing along the magnetic field lines linking the magnetosphere and the high-latitude ionosphere. Mercury is unique in that it is expected that FACS will be very short lived due to the low electrical conductivity of the regolith. Furthermore, at the earth it has been shown that the outflow of neutral atmospheric species to great altitudes is an important source of magnetospheric plasma (following ionization) whose composition may influence subsequent magnetotail dynamics. However, the dominant source of plasma for most of the terrestrial magnetosphere is the 'leakage'of solar wind across the magnetopause and more

  15. Theory of ballooning-mirror instabilities for anisotropic pressure plasmas in the magnetosphere

    SciTech Connect

    Cheng, C.Z.; Qian, Q.

    1993-09-01

    This paper deals with a kinetic-MHD eigenmode stability analysis of low frequency ballooning-mirror instabilities for anisotropic pressure plasmas in the magnetosphere. The ballooning mode is a dominant transverse wave driven unstable by pressure gradient in the bad curvature region. The mirror mode with a dominant compressional magnetic field perturbation is excited when the product of plasma beta and pressure anisotropy is large. The field-aligned eigenmode equations take into account the coupling of the transverse and compressional components of the perturbed magnetic field and describe the coupled ballooning-mirror mode. Because the energetic trapped ions precess very rapidly across the {rvec B} field, their motion becomes very rigid with respect to low frequency MHD perturbations with symmetric structure of parallel perturbed magnetic field {delta}B{sub {parallel}} and electrostatic potential {Phi} along the north-south ambient magnetic field, and the symmetric ballooning-mirror mode is shown to be stable. On the other hand, the ballooning-mirror mode with antisymmetric {delta}B{sub {parallel}}, and {Phi} structure along the north-south ambient magnetic field is only weakly influenced by energetic trapped particle kinetic effects due to rapid trapped particle bounce motion and has the lowest instability threshold determined by MHD theory. With large plasma beta ({beta}{sub {parallel}} {ge} O(1)) and pressure anisotropy (P{sub {perpendicular}}/P{sub {parallel}} > 1) at equator the antisymmetric ballooning-mirror mode structures resemble the field-aligned wave structures of the multisatellite observations of a long lasting compressional Pc 5 wave event during November 14--15, 1979 [Takahashi et al.]. The study provides the theoretical basis for identifying the internal excitation mechanism of ULF (Pc 4-5) waves by comparing the plasma stability parameters computed from the satellite particle data with the theoretical values.

  16. Storm time plasma transport in a unified and inter-coupled global magnetosphere model

    NASA Astrophysics Data System (ADS)

    Ilie, R.; Liemohn, M. W.; Toth, G.

    2014-12-01

    We present results from the two-way self-consistent coupling between the kinetic Hot Electron and Ion Drift Integrator (HEIDI) model and the Space Weather Modeling Framework (SWMF). HEIDI solves the time dependent, gyration and bounced averaged kinetic equation for the phase space density of different ring current species and computes full pitch angle distributions for all local times and radial distances. During geomagnetic times the dipole approximation becomes unsuitable even in the inner magnetosphere. Therefore the HEIDI model was generalized to accommodate an arbitrary magnetic field and through the coupling with SWMF it obtains a magnetic field description throughout the HEIDI domain along with a plasma distribution at the model outer boundary from the Block Adaptive Tree Solar Wind Roe Upwind Scheme (BATS-R-US) magnetohydrodynamics (MHD) model within SWMF. Electric field self-consistency is assured by the passing of convection potentials from the Ridley Ionosphere Model (RIM) within SWMF. In this study we test the various levels of coupling between the 3 physics based models, highlighting the role that the magnetic field, plasma sheet conditions and the cross polar cap potential play in the formation and evolution of the ring current. We show that the dynamically changing geospace environment itself plays a key role in determining the geoeffectiveness of the driver. The results of the self-consistent coupling between HEIDI, BATS-R-US and RIM during disturbed conditions emphasize the importance of a kinetic self-consistent approach to the description of geospace.

  17. The polarization electric field and its effects in an anisotropic rotating magnetospheric plasma

    NASA Technical Reports Server (NTRS)

    Huang, T. S.; Birmingham, T. J.

    1992-01-01

    Spatial variations of density and temperature along a magnetic field line are evaluated for a plasma undergoing adiabatic motion in a rotating magnetosphere. The effects of centrifugal and gravitational forces are accounted for, as is anisotropy in the pitch angle distribution functions of individual species. A polarization electric field is invoked to eliminate the net electric charge density resulting from the aforementioned mass dependent forces and different anisotropies. The position of maximum density in a two-component, electron-ion plasma is determined both in the absence and in the presence of the polarization effect and compared. A scale height, generalized to include anisotropies, is derived for the density fall-off. The polarization electric field is also included in the parallel guiding center equation; equilibrium points are determined and compared in both individual and average senses with the position of density maximum. Finally a transverse (to magnetic field lines) electric component is deduced as a consequence of dissimilar charge neutralization on adjacent field lines. The E x B velocity resultant from such a 'fringing' electric field is calculated and compared with the magnitude of other drifts.

  18. Numerical simulation of torus-driven plasma transport in the Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Yang, Y. S.; Wolf, R. A.; Spiro, R. W.; Hill, T. W.; Dessler, A. J.

    1994-01-01

    The Rice convection model has been modified for application to the transport of Io-generated plasma through the Jovian magnetosphere. The new code, called the RCM-J, has been used for several ideal-magnetohydrodynamic (MHD) numerical simulations to study how interchange instability causes an initially assumed torus configuration to break up. In simulations that start from a realistic torus configuration but include no energetic particles, the torus disintegrates too quickly (approximately 50 hours). By adding an impounding distribution of energetic particles to suppress the interchange instability, resonable lifetimes were obtained. For cases in which impoundment is insufficient to produce ideal-MHD stability, the torus breaks up predominantly into long fingers, unless the initial condition strongly favors some other geometrical form. If the initial torus has more mass on one side of the planet than the other, fingers form predominatly on the heavy side (which we associate with the active sector). Coriolis force bends the fingers to lag corotation. The simulation results are consistent with the idea that the fingers are formed with a longitudinal thickness that is roughly equal to the latitudinal distance over which the invariant density declines at the outer edges of the initial torus. Our calculations give an average longitudinal distance between plasma fingers of about 15 deg which corresponds to 20 to 30 minutes of rotation of the torus. We point to some Voyager and Ulysses data that are consistent with this scale of torus longitudinal irregularity.

  19. Magnetospheric Multiscale Observations of Electron Vortex Magnetic Hole in the Turbulent Magnetosheath Plasma

    NASA Astrophysics Data System (ADS)

    Huang, S. Y.; Sahraoui, F.; Yuan, Z. G.; He, J. S.; Zhao, J. S.; Le Contel, O.; Deng, X. H.; Zhou, M.; Fu, H. S.; Shi, Q. Q.; Lavraud, B.; Pang, Y.; Yang, J.; Wang, D. D.; Li, H. M.; Yu, X. D.; Pollock, C. J.; Giles, B. L.; Torbert, R. B.; Russell, C. T.; Goodrich, K. A.; Gershman, D. J.; Moore, T. E.; Ergun, R. E.; Khotyaintsev, Y. V.; Lindqvist, P.-A.; Strangeway, R. J.; Magnes, W.; Bromund, K.; Leinweber, H.; Plaschke, F.; Anderson, B. J.; Burch, J. L.

    2017-02-01

    We report on the observations of an electron vortex magnetic hole corresponding to a new type of coherent structure in the turbulent magnetosheath plasma using the Magnetospheric Multiscale mission data. The magnetic hole is characterized by a magnetic depression, a density peak, a total electron temperature increase (with a parallel temperature decrease but a perpendicular temperature increase), and strong currents carried by the electrons. The current has a dip in the core region and a peak in the outer region of the magnetic hole. The estimated size of the magnetic hole is about 0.23 ρ i (∼30 ρ e) in the quasi-circular cross-section perpendicular to its axis, where ρ i and ρ e are respectively the proton and electron gyroradius. There are no clear enhancements seen in high-energy electron fluxes. However, there is an enhancement in the perpendicular electron fluxes at 90° pitch angle inside the magnetic hole, implying that the electrons are trapped within it. The variations of the electron velocity components V em and V en suggest that an electron vortex is formed by trapping electrons inside the magnetic hole in the cross-section in the M–N plane. These observations demonstrate the existence of a new type of coherent structures behaving as an electron vortex magnetic hole in turbulent space plasmas as predicted by recent kinetic simulations.

  20. Plasma waves and electrostatic structures near propagating boundary layers in the inner terrestrial magnetosphere: Van Allen Probes and THEMIS observations

    NASA Astrophysics Data System (ADS)

    Malaspina, David; Wygant, John; Ergun, Robert; Reeves, Geoff; Skoug, Ruth; Larsen, Brian

    2016-10-01

    A broad range of plasma wave phenomena, only recently reported in the near-equatorial inner terrestrial magnetosphere, have been detected using the Van Allen Probes. These phenomena include electrostatic structures, such as double layers and phase space holes, as well as plasma wave modes including nonlinearly steepened whistler waves and kinetic Alfvén waves. The ubiquity of these structures is now confirmed, but it is not understood what role these structures and waves play in the dynamics of the inner magnetosphere and radiation belts. To quantify their importance, it is necessary to understand their distribution, generation, and impact on particle populations. In this study, we demonstrate a strong correlation between the occurrence of these phenomena and plasma boundaries, including the inner edge of the plasma sheet, propagating injection fronts, and the plasmapause. Further, we find that these structures and waves are continually generated as these boundaries propagate through the inner magnetosphere. Understanding the generation mechanisms of these structures and waves, as well as their impact on particle populations stands to benefit significantly from careful theoretical treatment, numerical simulation, and laboratory experiments.

  1. Future beam experiments in the magnetosphere with plasma contactors: How do we get the charge off the spacecraft?

    NASA Astrophysics Data System (ADS)

    Delzanno, G. L.; Borovsky, J. E.; Thomsen, M. F.; Moulton, J. D.; MacDonald, E. A.

    2015-05-01

    The idea of using a high-voltage electron beam with substantial current to actively probe magnetic field line connectivity in space has been discussed since the 1970s. However, its experimental realization onboard a magnetospheric spacecraft has never been accomplished because the tenuous magnetospheric plasma cannot provide the return current necessary to keep spacecraft charging under control. In this work, we perform Particle-In-Cell simulations to investigate the conditions under which a high-voltage electron beam can be emitted from a spacecraft and explore solutions that can mitigate spacecraft charging. The electron beam cannot simply be compensated for by an ion beam of equal current, because the Child-Langmuir space charge limit is violated under conditions of interest. On the other hand, releasing a high-density neutral contactor plasma prior and during beam emission is critical in aiding beam emission. We show that after an initial transient controlled by the size of the contactor cloud where the spacecraft potential rises, the spacecraft potential can settle into conditions that allow for electron beam emission. A physical explanation of this result in terms of ion emission into spherical geometry from the surface of the plasma cloud is presented, together with scaling laws of the peak spacecraft potential varying the ion mass and beam current. These results suggest that a strategy where the contactor plasma and the electron beam operate simultaneously might offer a pathway to perform beam experiments in the magnetosphere.

  2. Shape of the terrestrial plasma sheet in the near-Earth magnetospheric tail as imaged by the Interstellar Boundary Explorer

    SciTech Connect

    Dayeh, M. A.; Fuselier, S. A.; Funsten, H. O.; McComas, D. J.; Ogasawara, K.; Petrinec, S. M.; Schwadron, N. A.; Valek, P.

    2015-04-11

    We present remote, continuous observations from the Interstellar Boundary Explorer of the terrestrial plasma sheet location back to -16 Earth radii (RE) in the magnetospheric tail using energetic neutral atom emissions. The time period studied includes two orbits near the winter and summer solstices, thus associated with large negative and positive dipole tilt, respectively. Continuous side-view images reveal a complex shape that is dominated mainly by large-scale warping due to the diurnal motion of the dipole axis. Superposed on the global warped geometry are short-time fluctuations in plasma sheet location that appear to be consistent with plasma sheet flapping and possibly twisting due to changes in the interplanetary conditions. We conclude that the plasma sheet warping due to the diurnal motion dominates the average shape of the plasma sheet. Over short times, the position of the plasma sheet can be dominated by twisting and flapping.

  3. Shape of the terrestrial plasma sheet in the near-Earth magnetospheric tail as imaged by the Interstellar Boundary Explorer

    DOE PAGES

    Dayeh, M. A.; Fuselier, S. A.; Funsten, H. O.; ...

    2015-04-11

    We present remote, continuous observations from the Interstellar Boundary Explorer of the terrestrial plasma sheet location back to -16 Earth radii (RE) in the magnetospheric tail using energetic neutral atom emissions. The time period studied includes two orbits near the winter and summer solstices, thus associated with large negative and positive dipole tilt, respectively. Continuous side-view images reveal a complex shape that is dominated mainly by large-scale warping due to the diurnal motion of the dipole axis. Superposed on the global warped geometry are short-time fluctuations in plasma sheet location that appear to be consistent with plasma sheet flapping andmore » possibly twisting due to changes in the interplanetary conditions. We conclude that the plasma sheet warping due to the diurnal motion dominates the average shape of the plasma sheet. Over short times, the position of the plasma sheet can be dominated by twisting and flapping.« less

  4. Magnetospheric plasma studies using data from the dynamics explorer high and low altitude plasma instruments

    NASA Astrophysics Data System (ADS)

    Barfield, J. N.

    1986-02-01

    The reported research focused primarily upon plasma processes in and near the plasma cusp. The following areas were studied: plasma injection and transport in the mid-altitude polar cusp; observations of counterstreaming electrons at high altitudes; observations of upward electron beams and their relationship to region 1 Birkeland currents; observations of the electron population responsible for the 6300A SAR arc emission, polar rain observations; polar wind observations; and observations of ion and electron acceleration events produced by parallel electric fields. The primary observing platform for the research reported here was Dynamic Explorer 1 (DE-1). The DE-1 High Altitude Plasma Instrument (HAPI) consists of five electrostatic analyzers mounted in a fan-shaped angular array at angles of 45, 78, 90, 102, and 135 deg. with respect to the spacecraft spin axis. Each analyzer makes differential measurements of electrons and positive ions over an energy/charge range of 5 eV/e to 32 keV/e. Energy stepping proceeds at commandable rates of up to 64 sec, providing three-dimensional plasma distribution functions at the six second spin rate or DE-1.

  5. Investigating the energy crisis in Io's plasma torus: plasma energetics in rotating magnetospheres

    NASA Astrophysics Data System (ADS)

    Ramer, K. M.; Kivelson, M.; Vogt, M.; Khurana, K. K.; Walker, R. J.; Strangeway, R. J.

    2015-12-01

    It has long been recognized that there is something lacking in our understanding of the temperature of the Io plasma torus. In situ observations show that the temperature in the torus increases more than can be accounted for by ion pickup; as much as 20% of the needed energy is missing. However, the role of centrifugal acceleration has not been investigated as a potential source of plasma heating. Analysis of the role of centrifugal forces on the plasma population is difficult as the effects are both energy and pitch-angle dependent: adiabatic outward displacement of flux tubes in a rotating frame results in net cooling of equatorially mirroring plasma even when a centrifugal force is acting, but this is not necessarily the case for particles mirroring off the equator. An ion in a rotating, adiabatically stretching system bouncing away from its mirror point will gain parallel energy from the centrifugal force, but will lose it again as it moves back towards its mirror point; the bounce-averaged change in energy is small. Therefore the centrifugal force in an adiabatically expanding system is only able to impart significant energy to a particle if the timescale of the stretching is less than that of a bounce period. As a prelude to a full Large Scale Kinetic (LSK) simulation of particles in a rotating magnetic field, here we check that two prerequisite conditions are met. Firstly, we estimate an upper bound to the thermal energy that could be gained through centrifugal acceleration in order to demonstrate that there is sufficient energy to account for the temperature anomaly observed at Io's plasma torus. Secondly, we calculate the bounce period of ions typical to the torus to establish the range of energies for which the quarter bounce times are is shorter than the ~4 days required for the field in the Io plasma torus to stretch from 6-10 RJ. We will also describe preliminary results from our modeling efforts.

  6. Distribution of turbulent plasma in the magnetosphere estimated by the SWARM magnetic data.

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Iyemori, T.; Nakanishi, K.; Aoyama, T.

    2015-12-01

    LEO satellites observe the magnetic fluctuations with period from a few second to a few tens of seconds along their orbits in high-latitudes. It has been proposed that these are mainly caused by the spatial structures of the field-aligned currents(FACs). However, since LEO satellites before the SWARM were single, the studies still have theoretical assumptions. In this study, at first, we will show that these fluctuations are the manifestations of the spatial structures of the FACs by using the data obtained by SWARM-satellites during initial two months. Second, based on the above, we assume that these fluctuations mainly consist of the spatial variations, and apply spectral analysis to see the characteristics of the spatial structure of the FACs. From the above analyses, we confirm that the fluctuations with period from about 2 second to about 30 second can be regarded as the manifestations of the spatial structure of FACs. Then we project the area of fluctuations on the equatorial plane of magnetosphere, i.e., the plasma sheet, by using the Tsyganenko model, and estimate the characteristics of turbulence. We will also show the relations between these turbulent region and the substorm phase etc.

  7. Competing mechanisms of plasma transport in inhomogeneous configurations with velocity shear: the solar-wind interaction with earth's magnetosphere.

    PubMed

    Faganello, M; Califano, F; Pegoraro, F

    2008-01-11

    Two-dimensional simulations of the Kelvin-Helmholtz instability in an inhomogeneous compressible plasma with a density gradient show that, in a transverse magnetic field configuration, the vortex pairing process and the Rayleigh-Taylor secondary instability compete during the nonlinear evolution of the vortices. Two different regimes exist depending on the value of the density jump across the velocity shear layer. These regimes have different physical signatures that can be crucial for the interpretation of satellite data of the interaction of the solar wind with the magnetospheric plasma.

  8. Magnetospheric plasma studies using data from the dynamics high and low altitude plasma instruments

    NASA Astrophysics Data System (ADS)

    Barfield, J. N.

    1984-05-01

    Plasma measurements made on Dynamics Explorer 1 and 2 spacecraft are providing new information on the altitude dependence of polar-cap plasma populations, their sources, and the acceleration processes they undergo. This study found that the polar-rain electron population apparently exhibits no significant altitude dependence between altitudes of a few hundred to approximately 20,000 km. This result was expected from the magnetosheath-like energy spectrum of the low-altitude polar rain. In this case of the polar wind, a significant velocity increase was theoretically predicted to occur between the two spacecraft altitudes, and this effect was confirmed by DE-1 plasma measurements. A major result of this study of the accelerated polar wind is its significant conic component, which indicates that the ions are heated perpendicularly as they emerge from the polar-cap ionosphere. The gradual decrease in polar-wind energy observed to occur from the cusp across to the nightside polar cap suggests that the perpendicular heating process, probably in cyclotron waves, is most intense near the cusp region. Significant altitude effects are also observed in the plasmas that occupy magnetic flux tubes connected to polar-cap auroral arcs (or theta auroras). At DE-2, typical low-energy (approximately 100 eV) inverted-V electron distributtions are observed. At DE-1 the electron and positive-ion distribution functions are consistent with electrostatic potential drops that are at times below the typical DE-1 altitude of 15,000 to 20,000 km and at times above these altitudes.

  9. Kinetic Space Weather: Toward a Global Hybrid Model of the Polar Ionosphere-Lower Magnetosphere Plasma Transport

    NASA Technical Reports Server (NTRS)

    Horwitz, James L.

    1996-01-01

    During the indicated period of performance, we had a number of publications concerned with kinetic polar ionosphere-lower magnetosphere plasma transport. For the IUGG 1991-4 Quadrennial Report, we reviewed aspects of U.S. accomplishments concerned with polar plasma transport, among other issues. In another review, we examined the computer simulations of multiple-scale processes in space plasmas, including polar plasma outflow and transport. We also examined specifically multiscale processes in ionospheric outflows. We developed a Generalized Semi-Kinetic(GSK) model for the topside-lower magnetosphere which explored the synergistic action of wave heating and electric potentials in the formation of auroral Ion conics, in particular the "pressure cooker" mechanism. We extended the GSK model all the way down to 120 km and applied this code to illustrate the response of the ionosphere- magnetosphere to soft-electron precipitation and convection-driven frictional ion heating, respectively. Later, the convection-driven heating work was extended to a paper for the Journal of Geophysical Research. In addition to the above full published papers, we also presented the first developments of the coupled fluid-semikinetic model for polar plasma transport during this period. The results from a steady-state treatment were presented, with the second presentation being concerned with the effects of photo-electrons on the polar wind, and the first garnering an outstanding student paper award from the American Geophysical Union. We presented the first results from a time-dependent version of this coupled fluid-semikinetic model.

  10. The Geometric Factor of Electrostatic Plasma Analyzers: A Case Study from the Fast Plasma Investigation for the Magnetospheric Multiscale mission

    NASA Technical Reports Server (NTRS)

    Collinson, Glyn A.; Dorelli, John Charles; Avanov, Leon A.; Lewis, Gethyn R.; Moore, Thomas E.; Pollock, Craig; Kataria, Dhiren O.; Bedington, Robert; Arridge, Chris S.; Chornay, Dennis J.; Gliese,Ulrik; Mariano, Al.; Barrie, Alexander C; Tucker, Corey; Owen, Christopher J.; Walsh, Andrew P.; Shappirio, Mark D.; Adrian, Mark L.

    2012-01-01

    We report our findings comparing the geometric factor (GF) as determined from simulations and laboratory measurements of the new Dual Electron Spectrometer (DES) being developed at NASA Goddard Space Flight Center as part of the Fast Plasma Investigation on NASA's Magnetospheric Multiscale mission. Particle simulations are increasingly playing an essential role in the design and calibration of electrostatic analyzers, facilitating the identification and mitigation of the many sources of systematic error present in laboratory calibration. While equations for laboratory measurement of the Geometric Factpr (GF) have been described in the literature, these are not directly applicable to simulation since the two are carried out under substantially different assumptions and conditions, making direct comparison very challenging. Starting from first principles, we derive generalized expressions for the determination of the GF in simulation and laboratory, and discuss how we have estimated errors in both cases. Finally, we apply these equations to the new DES instrument and show that the results agree within errors. Thus we show that the techniques presented here will produce consistent results between laboratory and simulation, and present the first description of the performance of the new DES instrument in the literature.

  11. P24 Plasma Physics Summer School 2012 Los Alamos National Laboratory Summer lecture series for students

    SciTech Connect

    Intrator, Thomas P.; Bauer, Bruno; Fernandez, Juan C.; Daughton, William S.; Flippo, Kirk A.; Weber, Thomas; Awe, Thomas J.; Kim, Yong Ho

    2012-09-07

    This report covers the 2012 LANL summer lecture series for students. The lectures were: (1) Tom Intrator, P24 LANL: Kick off, Introduction - What is a plasma; (2) Bruno Bauer, Univ. Nevada-Reno: Derivation of plasma fluid equations; (3) Juan Fernandez, P24 LANL Overview of research being done in p-24; (4) Tom Intrator, P24 LANL: Intro to dynamo, reconnection, shocks; (5) Bill Daughton X-CP6 LANL: Intro to computational particle in cell methods; (6) Kirk Flippo, P24 LANL: High energy density plasmas; (7) Thom Weber, P24 LANL: Energy crisis, fission, fusion, non carbon fuel cycles; (8) Tom Awe, Sandia National Laboratory: Magneto Inertial Fusion; and (9) Yongho Kim, P24 LANL: Industrial technologies.

  12. In Flight Calibration of the Magnetospheric Multiscale Mission Fast Plasma Investigation

    NASA Technical Reports Server (NTRS)

    Barrie, Alexander C.; Gershman, Daniel J.; Gliese, Ulrik; Dorelli, John C.; Avanov, Levon A.; Rager, Amy C.; Schiff, Conrad; Pollock, Craig J.

    2015-01-01

    The Fast Plasma Investigation (FPI) on the Magnetospheric Multiscale mission (MMS) combines data from eight spectrometers, each with four deflection states, into a single map of the sky. Any systematic discontinuity, artifact, noise source, etc. present in this map may be incorrectly interpreted as legitimate data and incorrect conclusions reached. For this reason it is desirable to have all spectrometers return the same output for a given input, and for this output to be low in noise sources or other errors. While many missions use statistical analyses of data to calibrate instruments in flight, this process is insufficient with FPI for two reasons: 1. Only a small fraction of high resolution data is downloaded to the ground due to bandwidth limitations and 2: The data that is downloaded is, by definition, scientifically interesting and therefore not ideal for calibration. FPI uses a suite of new tools to calibrate in flight. A new method for detection system ground calibration has been developed involving sweeping the detection threshold to fully define the pulse height distribution. This method has now been extended for use in flight as a means to calibrate MCP voltage and threshold (together forming the operating point) of the Dual Electron Spectrometers (DES) and Dual Ion Spectrometers (DIS). A method of comparing higher energy data (which has low fractional voltage error) to lower energy data (which has a higher fractional voltage error) will be used to calibrate the high voltage outputs. Finally, a comparison of pitch angle distributions will be used to find remaining discrepancies among sensors.

  13. In Flight Calibration of the Magnetospheric Multiscale Mission Fast Plasma Investigation

    NASA Technical Reports Server (NTRS)

    Barrie, Alexander C.; Gershman, Daniel J.; Gliese, Ulrik; Dorelli, John C.; Avanov, Levon A.; Salo, Chad L.; Tucker, Corey J.; Holland, Mathew P.; Pollock, Craig J.

    2015-01-01

    The Fast Plasma Investigation (FPI) on the Magnetospheric Multiscale mission (MMS) combines data from eight spectrometers, each with four deflection states, into a single map of the sky. Any systematic discontinuity, artifact, noise source, etc. present in this map may be incorrectly interpreted as legitimate data and incorrect conclusions reached. For this reason it is desirable to have all spectrometers return the same output for a given input, and for this output to be low in noise sources or other errors. While many missions use statistical analyses of data to calibrate instruments in flight, this process is difficult with FPI for two reasons: 1. Only a small fraction of high resolution data is downloaded to the ground due to bandwidth limitations and 2: The data that is downloaded is, by definition, scientifically interesting and therefore not ideal for calibration. FPI uses a suite of new tools to calibrate in flight. A new method for detection system ground calibration has been developed involving sweeping the detection threshold to fully define the pulse height distribution. This method has now been extended for use in flight as a means to calibrate MCP voltage and threshold (together forming the operating point) of the Dual Electron Spectrometers (DES) and Dual Ion Spectrometers (DIS). A method of comparing higher energy data (which has low fractional voltage error) to lower energy data (which has a higher fractional voltage error) will be used to calibrate the high voltage outputs. Finally, a comparison of pitch angle distributions will be used to find remaining discrepancies among sensors.

  14. Plasma variations in Saturn's inner magnetosphere from the main rings to Enceladus

    NASA Astrophysics Data System (ADS)

    Elrod, M. K.; Tseng, W. L.; Johnson, R. E.

    2011-10-01

    With the discovery of an oxygen atmosphere over Saturn's main rings by the Cassini spacecraft observation (Tokar et al., 2005; Johnson et al. 2006), as well a strong, but variable source from the plumes emanating from the southern polar region of the moon Enceladus (Porco et al., 2005; Smith et al., 2010) the physics of the inner magnetosphere from the main rings to inside the orbit of Enceladus has changed dramatically. This region contains O2 produced by the ring atmosphere and water group ions from the plumes. During the Saturn Orbit Insertion (SOI), July 1, 2004, Cassini detected a significant density of O2 + ions over the main rings and between the F & G rings suggestive of an oxygen atmosphere produced from photochemistry of the ice particles in Saturn's ring system (Johnson et al., 2006, Tseng et al., 2009, Tseng & Ip 2010). We have produced a simple photochemistry model combining the water products from Enceladus and the seasonal effects on the ring atmosphere. The purpose of this study is to examine ion densities and composition from several periapses passes from 2004 to 2010 for the region in order to separate contributions from the seasonal effect on the ring atmosphere from any contribution from water products coming from Enceladus. Due to the high background of this region, the number of orbits used in this study with good pointing into the plasma is limited to 6 passes, SOI, 2005(Sept 5), 2007(June 11, June 27/28), and 2010 (Mar 3, June 19). Our analysis indicates a large variation in ion density and temperature between 2004 and 2010 and between the Voyager 2 data. Although the Enceladus plumes are variable, the very large variability in the ion density and the changing composition from 2004 to equinox appears to be more consistent with the seasonal variation estimated for the ring

  15. Observation of a new high-β and high-density state of a magnetospheric plasma in RT-1

    NASA Astrophysics Data System (ADS)

    Saitoh, H.; Yano, Y.; Yoshida, Z.; Nishiura, M.; Morikawa, J.; Kawazura, Y.; Nogami, T.; Yamasaki, M.

    2014-08-01

    A new high-β and high-density state is reported for a plasma confined in a laboratory magnetosphere. In order to expand the parameter regime of an electron cyclotron resonance heating experiment, the 8.2 GHz microwave power of the Ring Trap 1 device has been upgraded with the installation of a new waveguide system. The rated input power launched from a klystron was increased from 25 to 50 kW, which enabled the more stable formation of a hot-electron high-β plasma. The diamagnetic signal (the averaged value of four magnetic loops signals) of a plasma reached 5.2 mWb. According to a two-dimensional Grad-Shafranov analysis, the corresponding local β value is close to 100%.

  16. Observation of a new high-β and high-density state of a magnetospheric plasma in RT-1

    SciTech Connect

    Saitoh, H.; Yano, Y.; Yoshida, Z.; Nishiura, M.; Morikawa, J.; Kawazura, Y.; Nogami, T.; Yamasaki, M.

    2014-08-15

    A new high-β and high-density state is reported for a plasma confined in a laboratory magnetosphere. In order to expand the parameter regime of an electron cyclotron resonance heating experiment, the 8.2 GHz microwave power of the Ring Trap 1 device has been upgraded with the installation of a new waveguide system. The rated input power launched from a klystron was increased from 25 to 50 kW, which enabled the more stable formation of a hot-electron high-β plasma. The diamagnetic signal (the averaged value of four magnetic loops signals) of a plasma reached 5.2 mWb. According to a two-dimensional Grad-Shafranov analysis, the corresponding local β value is close to 100%.

  17. Nonlinear dynamics of 3D beams of fast magnetosonic waves propagating in the ionospheric and magnetospheric plasma

    NASA Astrophysics Data System (ADS)

    Belashov, V. Yu.; Belashova, E. S.

    2016-11-01

    On the basis of the model of the three-dimensional (3D) generalized Kadomtsev-Petviashvili equation for magnetic field h = B / B the formation, stability, and dynamics of 3D soliton-like structures, such as the beams of fast magnetosonic (FMS) waves generated in ionospheric and magnetospheric plasma at a low-frequency branch of oscillations when β = 4 πnT/ B 2 ≪ 1 and β > 1, are studied. The study takes into account the highest dispersion correction determined by values of the plasma parameters and the angle θ = ( B, k), which plays a key role in the FMS beam propagation at those angles to the magnetic field that are close to π/2. The stability of multidimensional solutions is studied by an investigation of the Hamiltonian boundness under its deformations on the basis of solving of the corresponding variational problem. The evolution and dynamics of the 3D FMS wave beam are studied by the numerical integration of equations with the use of specially developed methods. The results can be interpreted in terms of the self-focusing phenomenon, as the formation of a stationary beam and the scattering and self-focusing of the solitary beam of FMS waves. These cases were studied with a detailed investigation of all evolutionary stages of the 3D FMS wave beams in the ionospheric and magnetospheric plasma.

  18. Inner magnetosphere coupling: Recent advances

    NASA Astrophysics Data System (ADS)

    Usanova, M. E.; Shprits, Y. Y.

    2017-01-01

    The dynamics of the inner magnetosphere is strongly governed by the interactions between different plasma populations that are coupled through large-scale electric and magnetic fields, currents, and wave-particle interactions. Inner magnetospheric plasma undergoes self-consistent interactions with global electric and magnetic fields. Waves excited in the inner magnetosphere from unstable particle distributions can provide energy exchange between different particle populations in the inner magnetosphere and affect the ring current and radiation belt dynamics. The ionosphere serves as an energy sink and feeds the magnetosphere back through the cold plasma outflow. The precipitating inner magnetospheric particles influence the ionosphere and upper atmospheric chemistry and affect climate. Satellite measurements and theoretical studies have advanced our understanding of the dynamics of various plasma populations in the inner magnetosphere. However, our knowledge of the coupling processes among the plasmasphere, ring current, radiation belts, global magnetic and electric fields, and plasma waves generated within these systems is still incomplete. This special issue incorporates extended papers presented at the Inner Magnetosphere Coupling III conference held 23-27 March 2015 in Los Angeles, California, USA, and includes modeling and observational contributions addressing interactions within different plasma populations in the inner magnetosphere (plasmasphere, ring current, and radiation belts), coupling between fields and plasma populations, as well as effects of the inner magnetosphere on the ionosphere and atmosphere.

  19. SOURCES AND SINKS OF NEUTRALS AND PLASMA IN THE SATURNIAN MAGNETOSPHERE (Invited)

    NASA Astrophysics Data System (ADS)

    Richardson, J. D.

    2009-12-01

    This talk will review current knowledge on the source and sinks of plasm and energy in Saturn's magnetosphere. Enceladus dominates the water group source, with most of the material escaping from the plume near the southern pole. The relatively low corotation energy in this region results in less energy being available to heat electrons. The electrons are too cold to ionize the neutrals and the inner magnetosphere is dominated by neutrals. In addition, Saturn's atmosphere is a large source of neutral H, the rings contribute O2, and Titan is a source whose magnitude is controversial. In the inner magnetosphere most particles and energy are removed as fast neutrals; transport is more important further out and may be dominated by fingers of inflow and outflow as at Jupiter.

  20. Modeling Magnetospheric Sources

    NASA Technical Reports Server (NTRS)

    Walker, Raymond J.; Ashour-Abdalla, Maha; Ogino, Tatsuki; Peroomian, Vahe; Richard, Robert L.

    2001-01-01

    We have used global magnetohydrodynamic, simulations of the interaction between the solar wind and magnetosphere together with single particle trajectory calculations to investigate the sources of plasma entering the magnetosphere. In all of our calculations solar wind plasma primarily enters the magnetosphere when the field line on which it is convecting reconnects. When the interplanetary magnetic field has a northward component the reconnection is in the polar cusp region. In the simulations plasma in the low latitude boundary layer (LLBL) can be on either open or closed field lines. Open field lines occur when the high latitude reconnection occurs in only one cusp. In the MHD calculations the ionosphere does not contribute significantly to the LLBL for northward IMF. The particle trajectory calculations show that ions preferentially enter in the cusp region where they can be accelerated by non-adiabatic motion across the high latitude electric field. For southward IMF in the MHD simulations the plasma in the middle and inner magnetosphere comes from the inner (ionospheric) boundary of the simulation. Solar wind plasma on open field lines is confined to high latitudes and exits the tailward boundary of the simulation without reaching the plasma sheet. The LLBL is populated by both ionospheric and solar wind plasma. When the particle trajectories are included solar wind ions can enter the middle magnetosphere. We have used both the MHD simulations and the particle calculations to estimate source rates for the magnetosphere which are consistent with those inferred from observations.

  1. The magnetosphere of Saturn

    NASA Technical Reports Server (NTRS)

    Schardt, A. W.

    1982-01-01

    Information about the magnetosphere of Saturn is provided: the magnetic dipole moment is axisymmetric, the bow shock stand-off distance is about 22 R sub S. The satellites Titan, Dione, and Tethys are probably the primary sources of magnetospheric plasma. Outside of approx. 4 R sub S, energetic particles are energized by diffusing inward while conserving their first and second adiabatic invariants. Particles are lost by satellite sweep-out, absorption byt the E ring and probably also by plasma interactions. The inner magnetosphere is characterized.

  2. Composition of hot ions /0.1-16 keV/e/ as observed by the GEOS and ISEE mass spectrometers and inferences for the origin and circulation of magnetospheric plasmas

    NASA Technical Reports Server (NTRS)

    Balsiger, H.

    1981-01-01

    The composition of hot magnetospheric plasma through different regions of the magnetosphere is described on the basis of mass spectrometer measurements by the GEOS 1, GEOS 2, and ISEE-1 spacecraft. Coordinated composition measurements on the different spacecraft also provide information on the spatial and temporal characteristics of the plasma during storms. Data on ion origins are also provided.

  3. Composition of hot ions /0. 1-16 keV/e/ as observed by the GEOS and ISEE mass spectrometers and inferences for the origin and circulation of magnetospheric plasmas

    SciTech Connect

    Balsiger, H.

    1981-01-01

    The composition of hot magnetospheric plasma through different regions of the magnetosphere is described on the basis of mass spectrometer measurements by the GEOS 1, GEOS 2, and ISEE-1 spacecraft. Coordinated composition measurements on the different spacecraft also provide information on the spatial and temporal characteristics of the plasma during storms. Data on ion origins are also provided.

  4. PIC simulations of a three component plasma described by Kappa distribution functions as observed in Saturn's magnetosphere

    NASA Astrophysics Data System (ADS)

    Barbosa, Marcos; Alves, Maria Virginia; Simões Junior, Fernando

    2016-04-01

    In plasmas out of thermodynamic equilibrium the particle velocity distribution can be described by the so called Kappa distribution. These velocity distribution functions are a generalization of the Maxwellian distribution. Since 1960, Kappa velocity distributions were observed in several regions of interplanetary space and astrophysical plasmas. Using KEMPO1 particle simulation code, modified to introduce Kappa distribution functions as initial conditions for particle velocities, the normal modes of propagation were analyzed in a plasma containing two species of electrons with different temperatures and densities and ions as a third specie.This type of plasma is usually found in magnetospheres such as in Saturn. Numerical solutions for the dispersion relation for such a plasma predict the presence of an electron-acoustic mode, besides the Langmuir and ion-acoustic modes. In the presence of an ambient magnetic field, the perpendicular propagation (Bernstein mode) also changes, as compared to a Maxwellian plasma, due to the Kappa distribution function. Here results for simulations with and without external magnetic field are presented. The parameters for the initial conditions in the simulations were obtained from the Cassini spacecraft data. Simulation results are compared with numerical solutions of the dispersion relation obtained in the literature and they are in good agreement.

  5. Nonlinear dynamics of the 3D FMS and Alfven wave beams propagating in plasma of ionosphere and magnetosphere

    NASA Astrophysics Data System (ADS)

    Belashov, Vasily

    We study the formation, structure, stability and dynamics of the multidimensional soliton-like beam structures forming on the low-frequency branch of oscillation in the ionospheric and magnetospheric plasma for cases when beta=4pinT/B(2) <<1 and beta>1. In first case with the conditions omega>{k_{yz}}(2,) v_{x}$<plasma parameters and the angle Theta=(B,k) [2]. In another case the dynamics of the finite-amplitude Alfvén waves propagating in the ionosphere and magnetosphere near-to-parallel to the field B is described by the 3D derivative nonlinear Schrödinger (3-DNLS) equation for the magnetic field of the wave h=(B_{y}+iB_{z})/2B/1-beta/ [3]. To study the stability of multidimensional solitons in both cases we use the method developed in [2] and investigated the Hamiltonian bounding with its deformation conserving momentum by solving the corresponding variation problem. To study evolution of solitons and their collision dynamics the proper equations were being integrated numerically using the codes specially developed and described in detail in [3]. As a result, we have obtained that in both cases for a single solitons on a level with wave spreading and collapse the formation of multidimensional solitons can be observed. These results may be interpreted in terms of self-focusing phenomenon for the FMS and Alfvén waves’ beam as stationary beam formation, scattering and self-focusing of wave beam. The soliton collisions on a level with known elastic interaction can lead to formation of complex structures including the multisoliton bound states. For all cases the problem of multidimensional soliton dynamics in the ionospheric and

  6. Analytical study of whistler mode waves in presence of parallel DC electric field for relativistic plasma in the magnetosphere of Uranus

    NASA Astrophysics Data System (ADS)

    Pandey, R. S.; Kaur, Rajbir

    2016-10-01

    In present paper, field aligned whistler mode waves are analyzed, in the presence of DC field in background plasma having relativistic distribution function in the magnetosphere of Uranus. The work has been examined for relativistic Maxwellian and loss-cone distribution function. In both the cases, we have studied the effect of various plasma parameters on the growth rate of waves by using the method of characteristics and discussed using data provided by Voyager 2. Growth rate has increased by increasing the magnitude of electric field, temperature anisotropy, energy density and number density of particles for Maxwellian and loss-cone background. However, when relativistic factor (λ =√{ 1 -v2 /c2 }) increases, growth rate decreases. The significant increase in real frequency of whistler waves can be observed. The results can be used for comparative study of planetary magnetospheres. The derivation can also be adapted to study various other instabilities in magnetosphere of Uranus.

  7. Planetary Rotation Modulation of Various Measured Plasma Parameters in Saturns Magnetosphere: a Possible Mechanism

    NASA Astrophysics Data System (ADS)

    Mitchell, D. G.; Brandt, P. C.; Carbary, J. F.; Krimigis, S. M.; Mauk, B. E.; Paranicas, C. P.; Roelof, E. C.; Jones, G.; Krupp, N.; Lagg, A.; Gurnett, D. A.; Kurth, W. S.; Dougherty, M. K.; Southwood, D. J.; Saur, J.; Zarka, P.

    2006-05-01

    The period of Saturn kilometric radiation (SKR) modulation established by Voyagers 1 and 2 in 1980 and 1981 (10 hours, 39 minutes, 22.4 +/- 7s) has been adopted by the International Astronomical Union as the official rotation period of Saturn. Other quantities seen to exhibit modulation at about the same period include the magnetic field, energetic electron spectral slope, and energetic neutral atom (ENA) emission. However first the Ulysses spacecraft, and later Cassini, have measured a significantly different the SKR period than the Voyagers (approximately 10 hours, 45minutes). This change is problematic, because if the field is truly locked to Saturns rotation, this would imply a huge change in angular momentum over a relatively short period. Furthermore, no consensus model has been accepted to explain how the effects of the rotation are communicated from the planetary body out to distances as large as over 20 Rs (Saturn radii). In this paper, we explore the possibility that the observed SKR period is not Saturns intrinsic rotation period, but rather stems from friction between the ionosphere and Saturns zonal wind flows. We suggest that the SKR location reflects a high conductivity anomaly in Saturns ionosphere, whereby rigid rotation is imposed on that part of the magnetosphere that connects via the magnetic field and field-aligned currents with this high conductivity anomaly (this is similar to the hypothesis of the camshaft model for the magnetic perturbation suggested by Espinosa et al., 2003). In that work, Espinosa et al. suggest that the high conductivity region exists because of a high order magnetic anomaly, that affects ionospheric conductivity locally. We extend that model to include a feed-back loop with the magnetosphere. In this scenario, a magnetospheric disturbance initially triggered by interaction with the field-aligned currents results in additional energy deposition in the ionosphere. This further increases the ionospheric conductivity, but

  8. The Pulsating Pulsar Magnetosphere

    NASA Astrophysics Data System (ADS)

    Tsui, K. H.

    2015-06-01

    Following the basic principles of a charge-separated pulsar magnetosphere, we consider the magnetosphere to be stationary in space, instead of corotating, and the electric field to be uploaded from the potential distribution on the pulsar surface, set up by the unipolar induction. Consequently, the plasma of the magnetosphere undergoes guiding center drifts of the gyromotion due to the forces transverse to the magnetic field. These forces are the electric force, magnetic gradient force, and field line curvature force. Since these plasma velocities are of drift nature, there is no need to introduce an emf along the field lines, which would contradict the {{E}\\parallel }={\\boldsymbol{E}} \\cdot {\\boldsymbol{B}} =0 plasma condition. Furthermore, there is also no need to introduce the critical field line separating the electron and ion open field lines. We present a self-consistent description where the magnetosphere is described in terms of electric and magnetic fields and also in terms of plasma velocities. The fields and velocities are then connected through the space-charge densities self-consistently. We solve the pulsar equation analytically for the fields and construct the standard steady-state pulsar magnetosphere. By considering the unipolar induction inside the pulsar and the magnetosphere outside the pulsar as one coupled system, and under the condition that the unipolar pumping rate exceeds the Poynting flux in the open field lines, plasma pressure can build up in the magnetosphere, in particular, in the closed region. This could cause a periodic opening up of the closed region, leading to a pulsating magnetosphere, which could be an alternative to pulsar beacons. The closed region can also be opened periodically by the build up of toroidal magnetic field through a positive feedback cycle.

  9. Electrostatic Bernstein waves in plasmas whose electrons have a dual kappa distribution: Applications to the Saturnian magnetosphere

    NASA Astrophysics Data System (ADS)

    Henning, F. D.; Mace, R. L.; Pillay, S. R.

    2011-12-01

    The dispersion relation for Bernstein mode waves in a plasma having a kappa distribution as the equilibrium velocity distribution for both hot and cool electron components is derived without the use of infinite sums of Bessel functions. In contrast to the single electron component case, points where the perpendicular group velocity vanishes, i.e., ∂ω/∂k$\\perp$ = 0, are found below the upper hybrid band. In the single electron species case only one such maximum/minimum is found in and above the upper hybrid band. However, in the case of two electron species, an additional maximum/minimum is observed. Our model is applied to conditions observed in the Saturnian magnetosphere where the emergence of these points may have important consequences for the interpretation of the observed microstructure.

  10. Performance of a Discrete Wavelet Transform for Compressing Plasma Count Data and its Application to the Fast Plasma Investigation on NASA's Magnetospheric Multiscale Mission

    NASA Technical Reports Server (NTRS)

    Barrie, Alexander C.; Yeh, Penshu; Dorelli, John C.; Clark, George B.; Paterson, William R.; Adrian, Mark L.; Holland, Matthew P.; Lobell, James V.; Simpson, David G.; Pollock, Craig J.; Moore, Thomas E.

    2015-01-01

    Plasma measurements in space are becoming increasingly faster, higher resolution, and distributed over multiple instruments. As raw data generation rates can exceed available data transfer bandwidth, data compression is becoming a critical design component. Data compression has been a staple of imaging instruments for years, but only recently have plasma measurement designers become interested in high performance data compression. Missions will often use a simple lossless compression technique yielding compression ratios of approximately 2:1, however future missions may require compression ratios upwards of 10:1. This study aims to explore how a Discrete Wavelet Transform combined with a Bit Plane Encoder (DWT/BPE), implemented via a CCSDS standard, can be used effectively to compress count information common to plasma measurements to high compression ratios while maintaining little or no compression error. The compression ASIC used for the Fast Plasma Investigation (FPI) on board the Magnetospheric Multiscale mission (MMS) is used for this study. Plasma count data from multiple sources is examined: resampled data from previous missions, randomly generated data from distribution functions, and simulations of expected regimes. These are run through the compression routines with various parameters to yield the greatest possible compression ratio while maintaining little or no error, the latter indicates that fully lossless compression is obtained. Finally, recommendations are made for future missions as to what can be achieved when compressing plasma count data and how best to do so.

  11. Satellite and Ground Signatures of Kinetic and Inertial Scale ULF Alfven Waves Propagating in Warm Plasma in Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Rankin, R.; Sydorenko, D.

    2015-12-01

    Results from a 3D global numerical model of Alfven wave propagation in a warm multi-species plasma in Earth's magnetosphere are presented. The model uses spherical coordinates, accounts for a non-dipole magnetic field, vertical structure of the ionosphere, and an air gap below the ionosphere. A realistic density model is used. Below the exobase altitude (2000 km) the densities and the temperatures of electrons, ions, and neutrals are obtained from the IRI and MSIS models. Above the exobase, ballistic (originating from the ionosphere and returning to ionosphere) and trapped (bouncing between two reflection points above the ionosphere) electron populations are considered similar to [Pierrard and Stegen (2008), JGR, v.113, A10209]. Plasma parameters at the exobase provided by the IRI are the boundary conditions for the ballistic electrons while the [Carpenter and Anderson (1992), JGR, v.97, p.1097] model of equatorial electron density defines parameters of the trapped electron population. In the simulations that are presented, Alfven waves with frequencies from 1 Hz to 0.01 Hz and finite azimuthal wavenumbers are excited in the magnetosphere and compared with Van Allen Probes data and ground-based observations from the CARISMA array of ground magnetometers. When short perpendicular scale waves reflect form the ionosphere, compressional Alfven waves are observed to propagate across the geomagnetic field in the ionospheric waveguide [e.g., Lysak (1999), JGR, v.104, p.10017]. Signals produced by the waves on the ground are discussed. The wave model is also applied to interpret recent Van Allen Probes observations of kinetic scale ULF waves that are associated with radiation belt electron dynamics and energetic particle injections.

  12. Observation of 'Band' Structures in Spacecraft Observations of Inner Magnetosphere Plasma Electrons

    NASA Astrophysics Data System (ADS)

    Mohan Narasimhan, Kirthika; Fazakerley, Andrew; Milhaljcic, Branislav; Grimald, Sandrine; Dandouras, Iannis; Owen, Chris

    2013-04-01

    In previous studies, several authors have reported inner magnetosphere observations of proton distributions confined to narrow energy bands in the range of 1-25 keV. These structures have been known as "nose structures", with reference to their appearance in energy-time spectrograms and are known as "bands" if they are observed for extended periods of time. These proton structures have been studied quite extensively with multiple mechanisms proposed for their formation, not all of which apply for electrons. We examine Double-Star TC1 PEACE electron data recorded in the inner magnetosphere (L<15) near the equatorial plane to see if these features are also observed in the electron energy spectra. These "bands" also appear in electron spectrograms, spanning an energy range of 0.2-30 keV, and are shown to occur predominantly towards the dayside and dusk sectors. We also see multiple bands in some instances. We investigate the properties of these multi-banded structures and carry out a statistical survey analysing them as a function of geomagnetic activity, looking at both the Kp and Auroral Indices, in an attempt to explain their presence.

  13. Inner Magnetosphere Imager Mission: A New Window on the Plasma Universe

    NASA Technical Reports Server (NTRS)

    Johnson, Charles L.; Herrmann, Melody

    1994-01-01

    The proposed Inner Magnetosphere Imager mission will obtain the first simultaneous images of the component regions of the inner magnetosphere and will enable scientists to relate these global images to internal and external influences, as well as local observations. We are performing at the George C. Marshall Space Flight Center a concept definition study of the proposed mission. The baseline mission calls for an instrument complement of approximately seven imagers to fly in an elliptical Earth orbit with an apogee of seven Earth radii (Re) and a perigee of approximately 4800 km. Several spacecraft concepts are being considered for the mission. The first concept utilizes a spinning spacecraft with a despun platform. The second concept splits the instruments onto two smaller satellites-a spinning spacecraft and a complementary three-axis stabilized spacecraft. Launch options being assessed for the spacecraft range from a Delta-2, for the single- and dual-spacecraft concepts, to dual Taurus launches, for the two smaller spacecraft. An additional option, that of downsizing the mission to fit within the guidelines of the Space Physics Division's new class of solar terrestrial probes, is also being considered.

  14. Observation of 'Band' Structures in Spacecraft Observations of Inner Magnetosphere Plasma Ions

    NASA Astrophysics Data System (ADS)

    Mohan, Kirthika; Fazakerley, Andrew; Grimald, Sandrine; Dandouras, Iannis; Owen, Chris

    2014-05-01

    In previous studies, several authors have reported inner magnetosphere observations of proton distributions confined to narrow energy bands in the range of 1-25 keV (Smith and Hoffman (1974), etc). These structures have been described as "nose structures", with reference to their appearance in energy-time spectrograms and are also known as "bands" if they occur for extended periods of time. Statistical surveys (Buzulukova et al. (2003); Vallat et al. (2007)) of these features in Interball and Cluster data highlight the presence of single nose in nightside sectors and multi-nose strutures in the dayside sectors. We examine Double-Star TC1 HIA data mainly recorded in the equatorial plane of the inner magnetosphere (L<15) to see how observations of "multi-banded structures" compare to the observations from more inclined orbits of Cluster and Interball. We investigate the properties of these multi-banded structures and carry out a statistical survey analysing them as a function of geomagnetic activity. This is a comparison study to a similar study conducted using DoubleStar TC-1 PEACE electron data.

  15. Studies for the Europagenic Plasma Source in Jupiter's Inner Magnetosphere during the Galileo Europa Mission

    NASA Technical Reports Server (NTRS)

    Smyth, William H.

    2004-01-01

    Progress in research to understand the three-dimensional nature of the Europagenic plasma torus is summarized. Efforts to improve the plasma torus description near Europa's orbit have included a better understanding of Europa's orbit and an improved description of the planetary magnetic field. New plasma torus chemistry for molecular and atomic species has been introduced and implemented in Europa neutral cloud models. Preliminary three-dimensional model calculations for Europa's neutral clouds and their plasma sources are presented.

  16. Saturn's outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Schardt, A. W.; Behannon, K. W.; Carbary, J. F.; Eviatar, A.; Lepping, R. P.; Siscoe, G. L.

    1983-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like Earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

  17. Helicon plasma generator-assisted surface conversion ion source for the production of H(-) ion beams at the Los Alamos Neutron Science Center.

    PubMed

    Tarvainen, O; Rouleau, G; Keller, R; Geros, E; Stelzer, J; Ferris, J

    2008-02-01

    The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H(-) ion beams in a filament-driven discharge. In this kind of an ion source the extracted H(-) beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H(-) converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H(-) ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H(-) ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H(-) production (main discharge) in order to further improve the brightness of extracted H(-) ion beams.

  18. Iogenic Plasma and its Rotation-Driven Transport in Jupiter's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Smyth, William H.

    2001-01-01

    Model calculations are reported for the Iogenic plasma source created by atomic oxygen and sulfur above Io's exobase in the corona and extended clouds (Outer Region). On a circumplanetary scale, two-dimensional distributions produced by integrating the proper three dimensional rate information for electron impact and charge exchange processes along the magnetic field lines are presented for the pickup ion rates, the net-mass and total-mass loading rates, the mass per unit magnetic flux rate, the pickup conductivity, the radial pickup current, and the net-energy loading rate for the plasma torus. All of the two-dimensional distributions are highly peaked at Io's location and hence highly asymmetric about Jupiter. The Iogenic plasma source is also calculated on a much smaller near-Io scale to investigate the structure of the highly peak rates centered about lo's instantaneous location. The Iogenic plasma source for the Inner Region (pickup rates produced below Io's exobase) is, however, expected to be the dominant source near lo for the formation of the plasma torus ribbon and to be a comparable source, if not a larger contributor, to the energy budget of the plasma torus, so as to provide the necessary power to sustain the plasma torus radiative loss rate.

  19. Overview - Electric fields. [in magnetosphere

    NASA Technical Reports Server (NTRS)

    Cauffman, D. P.

    1979-01-01

    The electric fields session is designed to review progress in observation, theory, and modeling of magnetospheric electric fields, and to expose important new results. The present report comments on the state and prospects of electric field research, with particular emphasis on relevance to quantitative modeling of the magnetospheric processes. Attention is given to underlying theories and models. Modeling philosophy is discussed relative to explanatory models and representative models. Modeling of magnetospheric electric fields, while in its infancy, is developing rapidly on many fronts employing a variety of approaches. The general topic of magnetospheric electric fields is becoming of prime importance in understanding space plasmas.

  20. Saturn: atmosphere, ionosphere, and magnetosphere.

    PubMed

    Gombosi, Tamas I; Ingersoll, Andrew P

    2010-03-19

    The Cassini spacecraft has been in orbit around Saturn since 30 June 2004, yielding a wealth of data about the Saturn system. This review focuses on the atmosphere and magnetosphere and briefly outlines the state of our knowledge after the Cassini prime mission. The mission has addressed a host of fundamental questions: What processes control the physics, chemistry, and dynamics of the atmosphere? Where does the magnetospheric plasma come from? What are the physical processes coupling the ionosphere and magnetosphere? And, what are the rotation rates of Saturn's atmosphere and magnetosphere?

  1. Plasma gradient effets on doubel-probe measurements in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Laakso, Harri; Aggson, Thomas L.; Pfaff, Robert F., Jr.

    1995-01-01

    The effects on double-probe electric field measurements induced by electron density and temperature gradients are investigated. We show that on some occasions such gradients may lead to marked spurious electric fields if the probes are assumed to lie at the same probe potential with repect to the plasma. The use of a proper bias current will decrease the magnitude of such an error. When the probes are near the plasma potential, the magnitude of these error signals, delta Epsilon, can vary as delta Epsilon approx. T(sub e)(Delta n(sub e)/n(sub e)) + 0.5 Delta T(sub e), where T(sub e) is the electron temperature, Delta n(sub e)/ n(sub e) the relative electron density variation between the two sensors, and Delta T(sub e) the electron temperature difference between the two sensors. This not only implies that the error signals will increase linearly with the density variations but also that such signatures grow with Delta T(sub e) i.e., such effects are 10 times larger in a 10-eV plasma than in a 1-eV plasma. This type of error is independent of the probe separation distance provided the gradient scale length is much larger than the distance. The largest errors occur when the probes are near to the plasma potential. During the crossing of a small structure (e.g, a double layer) the error signal appears as a bipolar signature. Our analysis shows that errors in double-probe measurements caused by plasma gradients are not significant at large scale (much greater than 1 km) plasma boundaries, and may only be important in cases where small-scale (less than 1 km), internal gradient structures exist. Bias currents tailored for each plasma parameter regime (i.e., variable bias current) would improve the double-probe response to gradient effects considerably.

  2. Global MHD model of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Wu, C. C.

    1983-01-01

    A global MHD model of the earth's magnetosphere is defined. An introduction to numerical methods for solving the MHD equations is given with emphasis on the shock-capturing technique. Finally, results concerning the shape of the magnetosphere and the plasma flows inside the magnetosphere are presented.

  3. The Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Birmingham, T. J.

    1983-01-01

    Research on Jovian magnetospheric physics from 1979 through 1982 is surveyed, with a focus on the observations of Voyagers 1 and 2. Jovian fields and plasmas are characterized in the order of their distance from the planet, and special emphasis is given to the Io plasma torus (IPT) in the 4.9-8-Jovian-radius region and to the extended Jovian magnetotail. Topics reviewed include synchrotron radiation, magnetic-field models, Na and S emissions in the IPT, aurora, the magnetic-anomaly model, IPT plasma diffusion-convection, Io-generated Alfven wave, plasma configuration beyond the IPT, low-energy charged particles, cosmic-ray-energy particles, particle acceleration, magnetic configuration, tail current sheet and plasma disc, magnetopause and magnetosheath, interplanetary ions of Jovian origin, and the Jovian magnetosphere at Saturnian distances.

  4. Oscillatory flow braking: inner magnetosphere observations

    NASA Astrophysics Data System (ADS)

    Panov, E. V.; Nakamura, R.; Baumjohann, W.; Angelopoulos, V.

    2013-12-01

    We search for damped oscillatory flow braking events observed by THEMIS/ARTEMIS in the near-Earth plasma sheet when their counterpart in the inner magnetosphere was observed. By comparing the particle and magnetic field data in the two locations we analyze the feedback of the inner magnetosphere to plasma sheet oscillatory flow braking. We discuss the possible role of the oscillatory flow events for plasma injection into the inner magnetosphere.

  5. Simulation of Tomographic Reconstruction of Magnetosphere Plasma Distribution By Multi-spacecraft Systems.

    NASA Astrophysics Data System (ADS)

    Kunitsyn, V.; Nesterov, I.; Andreeva, E.; Zelenyi, L.; Veselov, M.; Galperin, Y.; Buchner, J.

    A satellite radiotomography method for electron density distributions was recently proposed for closely-space multi-spacecraft group of high-altitude satellites to study the physics of reconnection process. The original idea of the ROY project is to use a constellation of spacecrafts (one main and several sub-satellites) in order to carry out closely-spaced multipoint measurements and 2D tomographic reconstruction of elec- tron density in the space between the main satellite and the subsatellites. The distances between the satellites were chosen to vary from dozens to few hundreds of kilometers. The easiest data interpretation is achieved when the subsatellites are placed along the plasma streamline. Then, whenever a plasma density irregularity moves between the main satellite and the subsatellites it will be scanned in different directions and we can get 2D distribution of plasma using these projections. However in general sub- satellites are not placed exactly along the plasma streamline. The method of plasma velocity determination relative to multi-spacecraft systems is considered. Possibilities of 3D tomographic imaging using multi-spacecraft systems are analyzed. The model- ing has shown that efficient scheme for 3D tomographic imaging would be to place spacecrafts in different planes so that the angle between the planes would make not more then ten degrees. Work is supported by INTAS PROJECT 2000-465.

  6. 3D Ion and Electron Distribution Function Measurements from the Fast Plasma Investigation on the Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Giles, B. L.; Pollock, C. J.; Avanov, L. A.; Barrie, A. C.; Burch, J. L.; Chandler, M. O.; Clark, G. B.; Coffey, V. N.; Dickson, C.; Dorelli, J.; Ergun, R. E.; Fuselier, S. A.; Gershman, D. J.; Gliese, U.; Holland, M. P.; Jacques, A. D.; Kreisler, S.; Lavraud, B.; MacDonald, E.; Mauk, B.; Moore, T. E.; Mukai, T.; Nakamura, R.; Paterson, W. R.; Rager, A. C.; Saito, Y.; Salo, C.; Sauvaud, J. A.; Torbert, R. B.; Vinas, A. F.; Yokota, S.

    2015-12-01

    The primary focus of the Magnetospheric Multiscale (MMS) mission, launched in March 2015, is magnetic reconnection and associated processes. Understanding hinges critically on the kinetic physics that allows reconnection to take place. The Fast Plasma Investigation (FPI) provides electron and ion distribution functions at 4.5s cadence and, for select periods of time, at cadences of 30ms for electrons and 150ms for ions. These select time periods are chosen after in situ acquisition based on inspection of the low resolution data. Thus the FPI provides, independent of spacecraft spin rate, the time resolution needed to resolve the small, fast-moving reconnection diffusion regions. The first mission phase focuses on the dayside magnetopause and this presentation is intended to demonstrate the capabilities of FPI to resolve the important spatial scales relevant to the reconnection process. Magnetopause and other boundary crossings will be examined and the phase-space trajectories identified at the tetrahedral satellite locations through analysis of the 3D distribution functions.

  7. A Theoretical Investigation of Solar Wind-Magnetosphere Interactions and Astrophysical Plasma Phenomena.

    DTIC Science & Technology

    1976-11-01

    catagories. First, some of the basic plasma physic of the cosmic rays transported to Earth has been considered in order to ascertain the bahavior of such...on blast wave theory applied to supernova remnants has progressed considerably further since our early work on the subject reported here under the category of papers to be published. (Author)

  8. The magnetospheric trough

    SciTech Connect

    Thomsen, M.F.; McComas, D.J.; Elphic, R.C.; Borovsky, J.E.

    1997-03-04

    The authors review the history of the concepts of the magnetospheric cold-ion trough and hot-electron trough and conclude that the two regions are actually essentially the same. The magnetospheric trough may be viewed as a temporal state in the evolution of convecting flux tubes. These flux tubes are in contact with the earth`s upper atmosphere which acts both as a sink for precipitating hot plasma sheet electrons and as a source for the cold ionospheric plasma leading to progressive depletion of the plasma sheet and refilling with cold plasma. Geosynchronous plasma observations show that the rate of loss of plasma-sheet electron energy density is commensurate with the precipitating electron flux at the low-latitude edge of the diffuse aurora. The rate at which geosynchronous flux tubes fill with cold ionospheric plasma is found to be consistent with previous estimates of early-time refilling. Geosynchronous observations further indicate that both Coulomb collisions and wave-particle effects probably play a role in trapping ionospheric material in the magnetosphere.

  9. Numerical Simulation of Rotation-Driven Plasma Transport In the Jovian Magnetosphere

    NASA Technical Reports Server (NTRS)

    Wolf, Richard A.

    1997-01-01

    A Jupiter version of the Rice Convection Model (RCM-J) was developed with support of an earlier NASA SR&T grant. The conversion from Earth to Jupiter included adding currents driven by centrifugal force, reversing the planetary magnetic field, and rescaling various parameters. A series of informative runs was carried out, all of them solving initial value problems. The simulations followed an initial plasma torus configuration as it fell apart by interchange instability. Some conclusions from the simulations were the following: 1. We confirmed that, for conventional values of the torus density and ionospheric conductance, the torus disintegrates by interchange instability on a time scale of approx. one day, which is 1-2 orders of magnitude shorter than the best estimates of the average residence time of plasma in the torus. 2. In the model, the instability could be slowed to an arbitrary degree by the addition of sufficient impounding energetic particles, as suggested earlier by Siscoe et al (1981). However, the observed energetic particles do not seem sufficient to guarantee impoundment (e.g., Mauk et al., 1996). 3. Whether inhibited by impoundment or not, the interchange was found to proceed by the formation of long fingers, which get thinner as they get longer. This picture differed dramatically from the conventional radial-diffusion picture (e.g., Siscoe and Summers (1981)), more superficially with the outward-moving-blob picture (Pontius and Hill, 1989). The obvious limitation of the original RCM-J was that it could not represent a plasma source. We could represent the decay of a pre-existing torus, but we could not represent the way ionization of material from Io continually replenishes the plasma. We consequently were precluded from studying a whole set of fundamental issues of torus theory, including whether the system can come to a steady state.

  10. 3D magnetospheric parallel hybrid multi-grid method applied to planet–plasma interactions

    SciTech Connect

    Leclercq, L.; Mancini, M.

    2016-03-15

    We present a new method to exploit multiple refinement levels within a 3D parallel hybrid model, developed to study planet–plasma interactions. This model is based on the hybrid formalism: ions are kinetically treated whereas electrons are considered as a inertia-less fluid. Generally, ions are represented by numerical particles whose size equals the volume of the cells. Particles that leave a coarse grid subsequently entering a refined region are split into particles whose volume corresponds to the volume of the refined cells. The number of refined particles created from a coarse particle depends on the grid refinement rate. In order to conserve velocity distribution functions and to avoid calculations of average velocities, particles are not coalesced. Moreover, to ensure the constancy of particles' shape function sizes, the hybrid method is adapted to allow refined particles to move within a coarse region. Another innovation of this approach is the method developed to compute grid moments at interfaces between two refinement levels. Indeed, the hybrid method is adapted to accurately account for the special grid structure at the interfaces, avoiding any overlapping grid considerations. Some fundamental test runs were performed to validate our approach (e.g. quiet plasma flow, Alfven wave propagation). Lastly, we also show a planetary application of the model, simulating the interaction between Jupiter's moon Ganymede and the Jovian plasma.

  11. Formation and evolution of flapping and ballooning waves in magnetospheric plasma sheet

    NASA Astrophysics Data System (ADS)

    Ma, J. Z. G.; Hirose, A.

    2016-05-01

    By adopting Lembége & Pellat's 2D plasma-sheet model, we investigate the flankward flapping motion and Sunward ballooning propagation driven by an external source (e.g., magnetic reconnection) produced initially at the sheet center. Within the ideal MHD framework, we adopt the WKB approximation to obtain the Taylor-Goldstein equation of magnetic perturbations. Fourier spectral method and Runge-Kutta method are employed in numerical simulations, respectively, under the flapping and ballooning conditions. Studies expose that the magnetic shears in the sheet are responsible for the flapping waves, while the magnetic curvature and the plasma gradient are responsible for the ballooning waves. In addition, the flapping motion has three phases in its temporal development: fast damping phase, slow recovery phase, and quasi-stabilized phase; it is also characterized by two patterns in space: propagating wave pattern and standing wave pattern. Moreover, the ballooning modes are gradually damped toward the Earth, with a wavelength in a scale size of magnetic curvature or plasma inhomogeneity, only 1-7% of the flapping one; the envelops of the ballooning waves are similar to that of the observed bursty bulk flows moving toward the Earth.

  12. A comparison of ULF fluctuations in the solar wind, magnetosheath, and dayside magnetosphere. I - Magnetosheath morphology. II - Field and plasma conditions in the magnetosheath

    NASA Technical Reports Server (NTRS)

    Engebretson, M. J.; Lin, N.; Baumjohann, W.; Luehr, H.; Anderson, B. J.

    1991-01-01

    Simultaneous data from ISEE 1 and 2 in the upstream solar wind, from AMPTE IRM in the subsolar magnetosheath, and from AMPTE CCE in the dayside magnetosphere are used to investigate the properties of the magnetosheath responsible for the transmission into the magnetosphere the ULF waves generated in the solar wind upstream of a quasi-parallel bow shock. The data are used to characterize the magnetosheath both during the periods when azimuthally polarized resonant harmonic ULF magnetic pulsations were observed in the dayside outer maagnetosphere, and when they were not. In addition, a detailed analysis is carried out of magnetic field and plasma conditions in the subsolar magnetosheath during these and other periods.

  13. Onset of magnetospheric substorms.

    NASA Technical Reports Server (NTRS)

    Tsurutani, B.; Bogott, F.

    1972-01-01

    An examination of the onset of magnetospheric substorms is made by using ATS 5 energetic particles, conjugate balloon X rays and electric fields, all-sky camera photographs, and auroral-zone magnetograms. It is shown that plasma injection to ATS distances, conjugate 1- to 10-keV auroral particle precipitation, energetic electron precipitation, and enhancements of westward magnetospheric electric-field component all occur with the star of slowly developing negative magnetic bays. No trapped or precipitating energetic-particle features are seen at ATS 5 when later sharp negative magnetic-bay onsets occur at Churchill or Great Whale River.

  14. Measurement of direct current electric fields and plasma flow speeds in Jupiter's magnetosphere

    NASA Technical Reports Server (NTRS)

    Kellogg, Paul J.; Goetz, K.; Howard, R. L.; Monson, S. J.; Balogh, A.; Forsyth, R. J.

    1993-01-01

    During the encounter of Ulysses with Jupiter, we have measured two components of the dc electric field and deduced from them the flow speed in the Io toms, as well as the presence of a polar cap region end what we interpret as a cleft region. Within the toms the flow speed is approximately equal to the speed of a plasma corotating with Jupiter but has significant deviations. The dominant deviations have an apparent period of the order of Jupiter's rotation period, but this might be a latitudinal effect. Other important periods are about 40 min and less than 25 min.

  15. The interaction between ULF waves and thermal plasma ions in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Zong, Qiugang

    2016-07-01

    During substorm activities, energetic particle injections associated with ULF waves have been detected when Cluster fleet was traveling inbound in the Southern Hemisphere. Substorm-injected energetic particles are strong and clearly modulated by these ULF waves. The ULF waves with the period of 1 min are probably the third harmonic mode. The periodic pitch angle dispersion signatures at 5.2-6.9 keV energy channel were detected by Cluster satellite. These thermal plasma have high coherence with the electric field of the third harmonic poloidal mode and satisfy the drift-bounce resonant condition of N = 2. In addition, ion outflows from the Earth's ionosphere (tens to hundreds of eV) are also observed to be modulated by these ULF waves. To the best of our knowledge, this is the first report to show that ULF waves can simultaneously interact with both substorm-injected "hot" particles from the magnetotail and cold outflow ions from the Earth's ionosphere.

  16. Global MHD Simulations of Space Plasma Environments: Heliosphere, Comets, Magnetospheres of Plants and Satellites

    NASA Technical Reports Server (NTRS)

    Kabin, K.; Hansen, K. C.; Gombosi, T. I.; Combi, M. R.; Linde, T. J.; DeZeeuw, D. L.; Groth, C. P. T.; Powell, K. G.; Nagy, A. F.

    2000-01-01

    Magnetohydrodynamics (MHD) provides an approximate description of a great variety of processes in space physics. Accurate numerical solutions of the MHD equations are still a challenge, but in the past decade a number of robust methods have appeared. Once these techniques made the direct solution of MHD equations feasible, a number of global three-dimensional models were designed and applied to many space physics objects. The range of these objects is truly astonishing, including active galactic nuclei, the heliosphere, the solar corona, and the solar wind interaction with planets, satellites, and comets. Outside the realm of space physics, MHD theory has been applied to such diverse problems as laboratory plasmas and electromagnetic casting of liquid metals. In this paper we present a broad spectrum of models of different phenomena in space science developed in the recent years at the University of Michigan. Although the physical systems addressed by these models are different, they all use the MHD equations as a unifying basis.

  17. Saturn's variable magnetosphere.

    PubMed

    Gombosi, Tamas I; Hansen, Kenneth C

    2005-02-25

    Since the Cassini spacecraft reached Saturn's orbit in 2004, its instruments have been sending back a wealth of data on the planet's magnetosphere (the region dominated by the magnetic field of the planet). In this Viewpoint, we discuss some of these results, which are reported in a collection of reports in this issue. The magnetosphere is shown to be highly variable and influenced by the planet's rotation, sources of plasma within the planetary system, and the solar wind. New insights are also gained into the chemical composition of the magnetosphere, with surprising results. These early results from Cassini's first orbit around Saturn bode well for the future as the spacecraft continues to orbit the planet.

  18. Physics of the Jovian Magnetosphere

    NASA Astrophysics Data System (ADS)

    Dessler, A. J.

    2002-08-01

    List of tables; Foreword James A. Van Allen; Preface; 1. Jupiter's magnetic field and magnetosphere Mario H. Acuña, Kenneth W. Behannon and J. E. P. Connerney; 2. Ionosphere Darrell F. Strobel and Sushil K. Atreya; 3. The low-energy plasma in the Jovian magnetosphere J. W. Belcher; 4. Low-energy particle population S. M. Krimigis and E. C. Roelof; 5. High-energy particles A. W. Schardt and C. K. Goertz; 6. Spectrophotometric studies of the Io torus Robert A. Brown, Carl B. Pilcher and Darrell F. Strobel; 7. Phenomenology of magnetospheric radio emissions T. D. Carr, M. D. Desch and J. K. Alexander; 8. Plasma waves in the Jovian magnetosphere D. A. Gurnett and F. L. Scarf; 9. Theories of radio emissions and plasma waves Melvyn L. Goldstein and C. K. Goertz; 10. Magnetospheric models T. W. Hill, A. J. Dessler and C. K. Goertz; 11. Plasma distribution and flow Vytenis M. Vasyliunas; 12. Microscopic plasma processes in the Jovian magnetosphere Richard Mansergh Thorne; Appendixes; References; Index.

  19. Magnetospheric protons and electrons encountered by the moon in the plasma sheet

    NASA Technical Reports Server (NTRS)

    Prakash, A.

    1975-01-01

    Results are summarized for a study of plasma-sheet particles (and their flow) encountered by the moon during its passage through the geomagnetic tail. The study is based on analysis of data obtained with a modulated Faraday cup on board the lunar-anchored spacecraft Explorer 35. It is shown that the electrons have a rapidly fluctuating non-Maxwellian energy distribution with a mean energy of several hundred electron volts and a density of approximately 0.2 per cu cm. Protons with energies of the order of 1 keV were usually detected above the instrument background when flowing towards earth at about 200 km/sec. It is suggested that strong terrestrial polar winds during the early history of the earth-moon system could have caused some erosion of the front side of the moon and that the relative smoothness of the same side could be explained in terms of gravitational shielding by the earth from the interplanetary rock flux.

  20. Magnetosphere imager science definition team interim report

    NASA Technical Reports Server (NTRS)

    Armstrong, T. P.; Johnson, C. L.

    1995-01-01

    For three decades, magnetospheric field and plasma measurements have been made by diverse instruments flown on spacecraft in may different orbits, widely separated in space and time, and under various solar and magnetospheric conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the magnetosphere. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data nd help explain complex magnetospheric processes, thus providing a clear picture of this region of space. This report documents the scientific rational for such a magnetospheric imaging mission and provides a mission concept for its implementation.

  1. Magnetosphere imager science definition team: Executive summary

    NASA Technical Reports Server (NTRS)

    Armstrong, T. P.; Gallagher, D. L.; Johnson, C. L.

    1995-01-01

    For three decades, magnetospheric field and plasma measurements have been made by diverse instruments flown on spacecraft in many different orbits, widely separated in space and time, and under various solar and magnetospheric conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the magnetosphere. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data and help explain complex magnetospheric processes, thus providing a clear picture of this region of space. This report summarizes the scientific rationale for such a magnetospheric imaging mission and outlines a mission concept for its implementation.

  2. Plasma in the Jovian magnetosphere: An X-ray and EUV study of the aurora and the Io plasma torus

    NASA Astrophysics Data System (ADS)

    Kraft, Ralph

    2013-09-01

    We propose 4x40 ks Chandra/HRC-I and 2x40 ks XMM-Newton observations of the Jovian aurora and Io plasma torus in conjunction with the Japanese SPRINT-A satellite. SPRINT-A will continuously observe Jupiter from Dec 2013 to Apr 2014, making sensitive EUV spectroscopic observations of the aurora and IPT. We will correlate variations in the X-ray flux from the aurora and IPT with changes in the EUV flux observed by SPRINT-A and with the properties of the solar wind. We will conclusively resolve the puzzle of the origin of the Jovian X-ray emission and determine if the precipitating particles originate from Io or from the solar wind.

  3. Constraining electric fields from electrostatic deflector plates: A brief report and case study from the Fast Plasma Investigation for the Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Collinson, Glyn A.; McFadden, James P.; Chornay, Dennis J.; Gershman, Daniel; Moore, Thomas E.

    2016-08-01

    A common feature of top hat space plasma analyzers are electrostatic "deflector plates" mounted externally to the aperture which steer the incoming particles and permit the sensor to rapidly scan the sky without moving. However, the electric fields generated by these plates can penetrate the mesh or grid on the outside of the sensor, potentially violating spacecraft electromagnetic cleanliness requirements. In this brief report we discuss how this issue was addressed for the Dual Electron Spectrometer for the Magnetospheric Multiscale Mission using a double-grid system and the simple modeling technique employed to assure the safe containment of the stray fields from its deflector plates.

  4. A quiescent magnetosphere for Neptune

    NASA Astrophysics Data System (ADS)

    Dessler, A. J.; Sandel, B. R.

    1989-08-01

    It is argued that, if Neptune has a large magnetic moment, a weak supply of plasma for its magnetosphere, and a magnetic moment that is in near alignment with the planetary spin axis, the Neptunian magnetosphere is almost completely quiescent except for a region near the magnetopause. There are two magnetic power sources: the flowing, magnetized solar wind, and the kinetic energy of planetery spin. It is predicted that Neptune has a magnetic moment of at least 1 G-RN to the 3rd, the sum of ionospheric and Triton injections of plasma into Neptune's magnetosphere is less than 1 kg/sec, and Neptune's dipole is aligned with the spin axis and located close to the center of the planet. The criterion for Neptune to be a quiescent magnetosphere is defined by the expenditure of less than 10 to the 9th Watts from all power sources.

  5. A quiescent magnetosphere for Neptune

    NASA Technical Reports Server (NTRS)

    Dessler, A. J.; Sandel, B. R.

    1989-01-01

    It is argued that, if Neptune has a large magnetic moment, a weak supply of plasma for its magnetosphere, and a magnetic moment that is in near alignment with the planetary spin axis, the Neptunian magnetosphere is almost completely quiescent except for a region near the magnetopause. There are two magnetic power sources: the flowing, magnetized solar wind, and the kinetic energy of planetery spin. It is predicted that Neptune has a magnetic moment of at least 1 G-RN to the 3rd, the sum of ionospheric and Triton injections of plasma into Neptune's magnetosphere is less than 1 kg/sec, and Neptune's dipole is aligned with the spin axis and located close to the center of the planet. The criterion for Neptune to be a quiescent magnetosphere is defined by the expenditure of less than 10 to the 9th Watts from all power sources.

  6. Observations of cold magnetospheric ions at geosynchronous orbit during times of high activity

    SciTech Connect

    Elphic, R.C.; Weiss, L.A.; Thomsen, M.F.; McComas, D.J.; Bame, S.J.

    1994-10-01

    Flowing, cold magnetospheric ions have been observed in conjunction with geosynchronous orbit magnetopause crossings since the earliest ATS and OGO missions. The authors have reported on the occurrence and convection of low-energy (10-100 eV) ions seen by multiple satellites in association with geosynchronous orbit magnetopause and low-latitude boundary layer (LLBL) encounters. More generally, Los Alamos 3-D plasma instruments observe these ions following storm sudden commencements (SSCs), when activity levels are high. The ions appear to be convecting radially outward and usually westward at speeds of a few to several tens of kilometers per second. Often the energy spectra reveal peaks at energies appropriate for cold convecting H{sup +}, He{sup +} and O{sup +}. The occurrence frequency distribution of these dense cold ions is peaked near 1400 LT, with an overall range from 1000 to beyond 1800 LT. This local time distribution is greatly skewed from the overall plasmaspheric distribution, which peaks closer to 1800 LT. Multisatellite observations show that the ions are seen first at late afternoon local times and then at progressively earlier and earlier local times (though usually no earlier than 1000 LT). This apparent evolution in local time suggests that the late-afternoon plasmaspheric plasma moves out and dawnward during times of increased magnetospheric activity. The three-satellite observations also allow the authors to track cold plasma convection at multiple points in the magnetosphere, and potentially provide a glimpse of the large-scale convection pattern.

  7. Global magnetosphere-like 3D structure formation in kinetics by hot magnetized plasma flow characterized by shape of the particle distribution function

    NASA Astrophysics Data System (ADS)

    Gubchenko, Vladimir

    The task was to provide an analytical elementary magnetosphere-like model in kinetics for verification of the 3D EM PIC codes created for space/aerospace and HED plasmas applications. Kinetic approach versus cold MHD approach takes into account different behavior in the EM fields of resonant and non resonant particles in the velocity phase space, which appears via shape characteristics of the particle velocity distribution function (PVDF) and via the spatial dispersion effect forming the collisionless dissipation in the EM fields. The external flow is a hot collisionless plasma characterized by the particle velocity distribution function (PVDF) with different shapes: Maxwellian, kappa, etc. The flow is in a “hot regime”: it can be supersonic but its velocity remains less the thermal velocity of the electrons. The “internal” part of the magnetosphere formed by trapped particles is the prescribed 3D stationary magnetization considered as a spherical “quasiparticle” with internal magnetodipole and toroidal moments represented as a broadband EM driver. We obtain after the linearization of Vlasov/Maxwell equations a self-consistent 3D large scale kinetic solution of the classic problem. Namely, we: model the “outer” part of the magnetosphere formed by external hot plasma flow of the flyby particles. Solution of the Vlasov equation expressed via a tensor of dielectric permittivity of nonmagnetized and magnetized flowing plasma. Here, we obtain the direct kinetic dissipative effect of the magnetotail formation and the opposite diamagnetic effect of the magnetosphere “dipolization”. We get MHD wave cone in flow magnetized by external guiding magnetic (GM) field. Magnetosphere in our consideration is a 3D dissipative “wave” package structure of the skinned EM fields formed by the “waves” excited at frequency bands where we obtain negative values and singularities (resonances) of squared EM refractive index of the cold plasma. The hot regime

  8. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder. Final report

    SciTech Connect

    Haines, D.M.; Reinisch, B.W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N{sub e}) as a function of height (the N{sub e} profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year. The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N{sub e} profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al.), has never been put into space. NASA`s 1990 Space Physics Strategy Implementation Study `The NASA Space Physics Program from 1995 to 2010` suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R{sub e} (Reiff et al.; Calvert et al.).

  9. The solar wind and magnetospheric dynamics

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1974-01-01

    The dynamic processes involved in the interaction between the solar wind and the earth's magnetosphere are reviewed. The evolution of models of the magnetosphere is first surveyed. The existence of the auroral substorm and the cyclical polar magnetic substorm is evidence that the magnetosphere is a dynamic system. The dynamic changes occurring in the magnetosphere, including erosion of the magnetopause, changes in the size of the polar cap, variations in the flaring angle of the tail, neutral point formation, plasma sheet motions, and the inward collapse of the midnight magnetosphere, are discussed. The cyclical variations of geomagnetic activity are explained in terms of the control of the solar wind-magnetosphere interaction by the north-south component of the interplanetary magnetic field. Present phenomenological models allow prediction of geomagnetic activity from interplanetary measurements, but modeling of detailed magnetospheric processes is still in its infancy.

  10. Electrodynamics of Pulsar Magnetospheres

    NASA Astrophysics Data System (ADS)

    Cerutti, Benoît; Beloborodov, Andrei M.

    2016-12-01

    We review electrodynamics of rotating magnetized neutron stars, from the early vacuum model to recent numerical experiments with plasma-filled magnetospheres. Significant progress became possible due to the development of global particle-in-cell simulations which capture particle acceleration, emission of high-energy photons, and electron-positron pair creation. The numerical experiments show from first principles how and where electric gaps form, and promise to explain the observed pulsar activity from radio waves to gamma-rays.

  11. Effect of the Interaction of Jovian Magnetosphere with Europa's Exosphere on Pick-up Ion Population and Plasma Environment

    NASA Astrophysics Data System (ADS)

    Borovikov, D.; Tenishev, V.; Jia, X.; Gombosi, T. I.

    2014-12-01

    With hypothesized liquid water ocean beneath its crust and observed large amount of oxygen in its exosphere, Europa is one of the potentially habitable locations of Solar system. This made the satellite the object of high scientific interest, the primary goal of Clipper mission drafted by NASA in particular. As of today, certain amount of data is already available (e.g. from Galileo spacecraft), yet more is awaited from Juno spacecraft, which is on its way to Jupiter. Europa's exosphere should be studied with connection with Jovian magnetosphere, as the two form together a complex system. They are tightly coupled through the processes of the magnetospheric ion sputtering, photolytic and electron reactions. Successful investigation of coupled system requires a simultaneous simulation of both its components. Previous approaches studied this system in a piece-wise manner. Our efforts presented here are aimed at developing of a more global approach that would combine the exosphere and magnetosphere into a single model. This approach is more complete as it accounts for mutual influence of Jovian magnetosphere and Europa's exosphere and allows us to study their time dependent interaction. We employed coupled MHD (Block-Adaptive Tree Solarwind Roe-type Upwind Scheme) and Monte-Carlo (Adaptive Mesh Particle Simulator) codes. Among the properties studied are distributions of pick-up ions (spatial, energy, pitch angle) and mass-loading of the magnetosphere in the vicinity of the satellite. A brief comparison of these properties with those resulted from previous works on the problem (Lipatov et al., 2010; Ip et al., 1998) and analysis of how introduced interaction of the satellite's atmosphere with Jovian magnitosphere changes the results are provided.

  12. Satellites of Uranus control its magnetosphere

    SciTech Connect

    Cheng, A.F.; Hill, T.W.

    1984-10-01

    The importance of the satellites of Uranus as sources of magnetospheric plasma were investigated. It is found that neither an Io like plasma source nor a Titan like source is likely at Uranus. The likely presence of a heavy ion plasma torus maintained by charged particle sputtering of the icy satellites is examined. Sputtering of Saturn's icy satellites is considered an important source of heavy ion (oxygen) plasma in Saturn's inner magnetosphere. A major unresolved question is whether this sputtering process does depend on the preexistence of magnetospheric heavy ions derived from another source, Titian.

  13. Los Alamos National Laboratory.

    ERIC Educational Resources Information Center

    Hammel, Edward F., Jr.

    1982-01-01

    Current and post World War II scientific research at the Los Alamos National Laboratory (New Mexico) is discussed. The operation of the laboratory, the Los Alamos consultant program, and continuation education, and continuing education activities at the laboratory are also discussed. (JN)

  14. Confinement and Transport in a Laboratory Magnetosphere

    NASA Astrophysics Data System (ADS)

    Peterson, Ethan; Clark, Michael; Cooper, Christopher; Endrizzi, Douglass; Wallace, John; Weisberg, David; Forest, Cary

    2016-10-01

    Measurements of density, temperature, diamagnetic currents, and ion flows throughout a dipole magnetosphere immersed in a homogeneous plasma are presented. A 1-D ambipolar diffusion transport model developed for multi-cusp confinement systems is adapted for a dipole magnetosphere geometry and compared to measurements. In addition, differential azimuthal flow is imposed on the magnetosphere through electrically driven flow at the boundary of the machine. Modifications to the transport and confinement due to differential rotation are presented as well.

  15. Saturn: An Inside-Out Magnetosphere

    NASA Astrophysics Data System (ADS)

    Thomsen, M. F.; Tokar, R. L.; Barraclough, B.; Delapp, D.; Funsten, H. O.; Reisenfeld, D.; Steinberg, J. T.; Sittler, E. C.; Hill, T. W.; Young, D. T.; Crary, F. J.; Andre, N.; Coates, A. J.

    2005-05-01

    At the Earth, the dominant sources of magnetospheric plasma are the solar wind and the upper atmosphere, both in a sense "external" to the magnetosphere itself. The path from source to sink is largely a solar-wind-driven convection into the magnetospheric tail, inward through and around the inner magnetosphere, and out through the dayside magnetopause. By contrast, at Saturn the magnetospheric plasma appears to be dominantly produced in situ, by local ionization of neutral material within the magnetospheric volume. Relevant evidence includes the plasma composition observed so far, the thermal structure, and the strong inward gradient in the density. There is also considerable evidence that this material is transported outward from the source region, at least in part through a very active process of centrifugally-driven flux-tube interchange. Ultimately, the plasma must be lost from the magnetosphere, through the magnetopause or down the tail as a planetary wind. We present observations from the Cassini CAPS instrument that demonstrate this "inside-out" character of Saturn's magnetospheric plasma sources, transport, and loss.

  16. RESISTIVE SOLUTIONS FOR PULSAR MAGNETOSPHERES

    SciTech Connect

    Li, Jason; Spitkovsky, Anatoly; Tchekhovskoy, Alexander

    2012-02-10

    The current state of the art in the modeling of pulsar magnetospheres invokes either the vacuum or force-free limits for the magnetospheric plasma. Neither of these limits can simultaneously account for both the plasma currents and the accelerating electric fields that are needed to explain the morphology and spectra of high-energy emission from pulsars. To better understand the structure of such magnetospheres, we combine accelerating fields and force-free solutions by considering models of magnetospheres filled with resistive plasma. We formulate Ohm's law in the minimal velocity fluid frame and construct a family of resistive solutions that smoothly bridges the gap between the vacuum and the force-free magnetosphere solutions. The spin-down luminosity, open field line potential drop, and the fraction of open field lines all transition between the vacuum and force-free values as the plasma conductivity varies from zero to infinity. For fixed inclination angle, we find that the spin-down luminosity depends linearly on the open field line potential drop. We consider the implications of our resistive solutions for the spin-down of intermittent pulsars and sub-pulse drift phenomena in radio pulsars.

  17. Measuring the magnetic connectivity of the geosynchronous region of the magnetosphere

    SciTech Connect

    Thomsen, M.; Hones, E.; McComas, D.; Reeves, G.; Weiss, L.

    1996-03-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was to determine the magnetic connectivity of the geosynchronous region of the magnetosphere to the auroral zone in the polar ionosphere in order to test and refine current magnetospheric magnetic field models. The authors used plasma data from LANL instruments on three geosynchronous satellites and from USAF instruments on three low-altitude, polar-orbiting, DMSP satellites. Magnetic connectivity is tested by comparing plasma energy spectra at DMSP and geosynchronous satellites when they are in near conjunction. The times of closest conjugacy are used to evaluate the field models. They developed the tools for each step of the process and applied them to the study of a one-week test set of conjunctions. They automated the analysis tools and applied them to four months of two-satellite observations. This produced a database of about 130 definitive magnetic conjunctions. They compared this database with the predictions of the widely-used Tsyganenko magnetic field model and showed that in most cases one of the various parameterizations of the model could reproduce the observed field line connection. Further, they explored various measurables (e.g., magnetospheric activity indices or the geosynchronous field orientation) that might point to the appropriate parameterization of the model for these conjunctions, and ultimately, for arbitrary times.

  18. Compressional perturbations of the dayside magnetosphere during high-speed-stream-driven geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Borovsky, Joseph E.; Denton, Michael H.

    2016-05-01

    The quasi-DC compressions of the Earth's dayside magnetic field by ram-pressure fluctuations in the solar wind are characterized by using multiple GOES spacecraft in geosynchronous orbit, multiple Los Alamos spacecraft in geosynchronous orbit, global MHD simulations, and ACE and Wind solar wind measurements. Owing to the inward-outward advection of plasma as the dayside magnetic field is compressed, magnetic field compressions experienced by the plasma in the dayside magnetosphere are greater than the magnetic field compressions measured by a spacecraft. Theoretical calculations indicate that the plasma compression can be a factor of 2 higher than the observed magnetic field compression. The solar wind ram-pressure changes causing the quasi-DC magnetospheric compressions are mostly owed to rapid changes in the solar wind number density associated with the crossing of plasma boundaries; an Earth crossing of a plasma boundary produces a sudden change in the dayside magnetic field strength accompanied by a sudden inward or outward motion of the plasma in the dayside magnetosphere. Superposed epoch analysis of high-speed-stream-driven storms was used to explore solar wind compressions and storm time geosynchronous magnetic field compressions, which are of particular interest for the possible contribution to the energization of the outer electron radiation belt. The occurrence distributions of dayside magnetic field compressions, solar wind ram-pressure changes, and dayside radial plasma flow velocities were investigated: all three quantities approximately obey power law statistics for large values. The approximate power law indices for the distributions of magnetic compressions and ram-pressure changes were both -3.

  19. Physics of magnetospheric boundary layers

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.

    1995-01-01

    This final report was concerned with the ideas that: (1) magnetospheric boundary layers link disparate regions of the magnetosphere-solar wind system together; and (2) global behavior of the magnetosphere can be understood only by understanding its internal linking mechanisms and those with the solar wind. The research project involved simultaneous research on the global-, meso-, and micro-scale physics of the magnetosphere and its boundary layers, which included the bow shock, the magnetosheath, the plasma sheet boundary layer, and the ionosphere. Analytic, numerical, and simulation projects were performed on these subjects, as well as comparisons of theoretical results with observational data. Other related activity included in the research included: (1) prediction of geomagnetic activity; (2) global MHD (magnetohydrodynamic) simulations; (3) Alfven resonance heating; and (4) Critical Ionization Velocity (CIV) effect. In the appendixes are list of personnel involved, list of papers published; and reprints or photocopies of papers produced for this report.

  20. Solar terrestrial coupling through space plasma processes

    SciTech Connect

    Birn, J.

    2000-12-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project investigates plasma processes that govern the interaction between the solar wind, charged particles ejected from the sun, and the earth's magnetosphere, the region above the ionosphere governed by the terrestrial magnetic field. Primary regions of interest are the regions where different plasma populations interact with each other. These are regions of particularly dynamic plasma behavior, associated with magnetic flux and energy transfer and dynamic energy release. The investigations concerned charged particle transport and energization, and microscopic and macroscopic instabilities in the magnetosphere and adjacent regions. The approaches combined space data analysis with theory and computer simulations.

  1. Fifty-one years of Los Alamos Spacecraft

    SciTech Connect

    Fenimore, Edward E.

    2014-09-04

    From 1963 to 2014, the Los Alamos National Laboratory was involved in at least 233 spacecraft. There are probably only one or two institutions in the world that have been involved in so many spacecraft. Los Alamos space exploration started with the Vela satellites for nuclear test detection, but soon expanded to ionospheric research (mostly barium releases), radioisotope thermoelectric generators, solar physics, solar wind, magnetospheres, astrophysics, national security, planetary physics, earth resources, radio propagation in the ionosphere, and cubesats. Here, we present a list of the spacecraft, their purpose, and their launch dates for use during RocketFest

  2. Stockpile Stewardship: Los Alamos

    ScienceCinema

    McMillan, Charlie; Morgan, Nathanial; Goorley, Tom; Merrill, Frank; Funk, Dave; Korzekwa, Deniece; Laintz, Ken

    2016-07-12

    "Heritage of Science" is a short video that highlights the Stockpile Stewardship program at Los Alamos National Laboratory. Stockpile Stewardship was conceived in the early 1990s as a national science-based program that could assure the safety, security, and effectiveness of the U.S. nuclear deterrent without the need for full-scale underground nuclear testing. This video was produced by Los Alamos National Laboratory for screening at the Lab's Bradbury Science Museum in Los Alamos, NM and is narrated by science correspondent Miles O'Brien.

  3. Global magnetohydrodynamic simulations of the magnetosphere

    SciTech Connect

    Walker, R.J.; Ogino, T.

    1989-04-01

    Global magnetohydrodynamic (MHD) simulations of the interaction between the solar wind and a planetary magnetosphere enable us to calculate self-consistently the time-dependent three-dimensional configuration of the magnetosphere. To demonstrate the application of a global MHD model to the magnetosphere, the authors have calculated the dependence of the magnetospheric configuration and polar-cap structure on the north-south component of the interplanetary magnetic field (IMF). First, they modeled the magnetosphere in the absence of an IMF and found a slowly evolving system in which steady convection leads to slow reconnection in the plasma sheet. When a uniform northward IMF was initially imposed throughout the system the plasma sheet thickened in a small region near the noon-midnight meridian and extended into the tail lobes. When viewed from the polar cap, this appears as a narrow finger of closed field lines extending into the polar cap. The plasma sheet thickening is caused by reconnection on the nightside magnetopause. This plasma sheet extension becomes less pronounced when the northward IMF enters the simulation box with the solar wind. For both cases the convection near midnight is toward the sun, and region-1-type field-aligned currents appear on both sides of the plasma sheet extension. For northward IMF the resulting magnetospheric configuration approached a quasi-steady state in which stable magnetospheric convection was maintained. The simulation results indicate that the presence of a northward B in the plasma sheet stabilizes the tail.

  4. Magnetospheric convection strength inferred from inner edge of the electron plasma sheet and its relation to the polar cap potential drop

    NASA Astrophysics Data System (ADS)

    Jiang, F.; Kivelson, M. G.; Walker, R. J.; Khurana, K. K.; Angelopoulos, V.

    2010-12-01

    The sharp inner edge of the nightside electron plasma sheet observed by the THEMIS spacecraft is shown to provide a measure of the effective convection strength that transports plasma sheet plasma into the inner magnetosphere. The effective convection strength is characterized by the difference of potential between the magnetopause terminators at dawn and at dusk. We have surveyed inner boundary crossings of the electron plasma sheet measured by three THEMIS probes on orbits from Nov. 2007 to Apr. 2009. The values of the convection electric potential are inferred from the locations of the inner edge for different energy channels using a steady-state drift boundary model with a dipole magnetic field and a Volland-Stern electric field. When plotted against the solar wind electric field ( ), the convection electric potential is found to have a quasi-linear relationship with the driving solar wind electric field for the range of values tested (meaningful statistics only for Esw < 1.5 mV/m). Reasonably good agreement is found between the convection electric potential and the polar-cap potential drop calculated from model of Boyle et al. [1997] when the degree of shielding in the Volland-Stern potential is selected as gamma=1.5.

  5. The Role of Self-Organized Criticality in the Substorm Phenomenon and its Relation to Localized Reconnection in the Magnetospheric Plasma Sheet

    NASA Technical Reports Server (NTRS)

    Klimas, Alex J.; Valdivia, J. A.; Vassiliadis, D.; Baker, D. N.; Hesse, M.; Takalo, J.

    1999-01-01

    Evidence is presented that suggests there is a significant self-organized criticality (SOC) component in the dynamics of substorms in the magnetosphere. Observations of BBFs, fast flows, localized dipolarizations, plasma turbulence, etc. are taken to show that multiple localized reconnection sites provide the basic avalanche phenomenon in the establishment of SOC in the plasma sheet. First results are presented from a continuing plasma physical study of this avalanche process. A one-dimensional resistive MHD model of a magnetic field reversal is discussed. Resistivity, in this model, is self-consistently generated in response to the excitation of an idealized current-driven instability. When forced by convection of magnetic flux into the field reversal region, the model yields rapid magnetic field annihilation through a dynamic behavior that is shown to exhibit many of the characteristics of SOC. Over a large range of forcing strengths, the annihilation rate is shown to self-adjust to balance the rate at which flux is convected into the reversal region. Several analogies to magnetotail dynamics are discussed: (1) It is shown that the presence of a localized criticality in the model produces a remarkable stability in the global configuration of the field reversal while simultaneously exciting extraordinarily dynamic internal evolution. (2) Under steady forcing, it is shown that a loading-unloading cycle may arise that, as a consequence of the global stability, is quasi-periodic and, therefore, predictable despite the presence of internal turbulence in the field distribution. Indeed, it is shown that the global loading-unloading cycle is a consequence of the internal turbulence. (3) It is shown that, under steady, strong forcing the loading-unloading cycle vanishes. Instead, a recovery from a single unloading persists indefinitely. The field reversal is globally very steady while internally it is very dynamic as field annihilation goes on at the rate necessary to

  6. Jupiter's magnetosphere and radiation belts

    NASA Technical Reports Server (NTRS)

    Kennel, C. F.; Coroniti, F. V.

    1979-01-01

    Radioastronomy and Pioneer data reveal the Jovian magnetosphere as a rotating magnetized source of relativistic particles and radio emission, comparable to astrophysical cosmic ray and radio sources, such as pulsars. According to Pioneer data, the magnetic field in the outer magnetosphere is radially extended into a highly time variable disk-shaped configuration which differs fundamentally from the earth's magnetosphere. The outer disk region, and the energetic particles confined in it, are modulated by Jupiter's 10 hr rotation period. The entire outer magnetosphere appears to change drastically on time scales of a few days to a week. In addition to its known modulation of the Jovian decametric radio bursts, Io was found to absorb some radiation belt particles and to accelerate others, and most importantly, to be a source of neutral atoms, and by inference, a heavy ion plasma which may significantly affect the hydrodynamic flow in the magnetosphere. Another important Pioneer finding is that the Jovian outer magnetosphere generates, or permits to escape, fluxes of relativistic electrons of such intensities that Jupiter may be regarded as the dominant source of 1 to 30 MeV cosmic ray electrons in the heliosphere.

  7. Explosive Flux Compression: 50 Years of Los Alamos Activities

    SciTech Connect

    Fowler, C.M.; Thomson, D.B.; Garn, W.B.

    1998-10-18

    Los Alamos flux compression activities are surveyed, mainly through references in view of space limitations. However, two plasma physics programs done with Sandia National Laboratory are discussed in more detail.

  8. Explosive Flux Compression:. 50 Years of LOS Alamos Activities

    NASA Astrophysics Data System (ADS)

    Fowler, C.; Thomson, D.; Garn, W.

    2004-11-01

    Los Alamos flux compression activities are surveyed, mainly through references in view of space limitations. However, two plasma physics programs done with Sandia National Laboratory are discussed in more detail.

  9. Currents and Flows in Distant Magnetospheres

    NASA Technical Reports Server (NTRS)

    Kivelson, Margaret Galland

    2000-01-01

    Space scientists have explored, described, and explained the terrestrial magnetosphere for four decades. Rarely do they point out that the planetary and solar wind parameters controlling the size, shape, and activity of Earth's magnetosphere map out only a small portion of the space of dimensionless parameters that govern magnetospheric properties. With the discovery of Ganymede's magnetosphere, the range of parameters relevant to magnetospheric studies has grown by orders of magnitude. Consider the extremes of Ganymede's and Jupiter's magnetospheres. Jupiter's magnetosphere forms within a plasma flowing at super-Alfvenic speed, whereas Ganymede's forms in a sub-Alfvenic flow. The scale sizes of these magnetospheres, characterized by distances to the magnetopause of order 7x10(exp 6) km and 5x10(exp 3) km, respectively, differ by three orders of magnitude, ranging from 100 to 0.1 times the scale of Earth's magnetosphere. The current systems that control the structure and dynamics of a magnetosphere depend on specific plasma and field properties. Magnetopause currents at Ganymede differ greatly from the forms familiar for Earth and Jupiter, principally because the Mach number of the ambient plasma flow greatly influences the shape of the magnetosphere. A magnetodisk current, present at Jupiter because of its rapid rotation, is absent at Earth and Ganymede. The ring current, extensively investigated at Earth, is probably unimportant at Ganymede because the dynamical variations of the external flow are slow. The ring current is subsumed within the magnetodisk current at Jupiter. This paper describes and contrasts aspects of these and other current systems for the three bodies.

  10. The electric field and global electrodynamics of the magnetosphere

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1979-01-01

    The conception of the electrodynamics of the quiet-time magnetosphere obtained during the last four years of magnetospheric study is presented. Current understandings of the open magnetosphere, convective plasma flows in the plasma sheet, the shielding of the inner magnetosphere from the convective magnetospheric electric field, the space charge produced when injected electrons drift towards dawn and injected ions drift towards dusk, the disruption of the flow of the Birkeland current by plasma instabilities and the shielding of the convective electric field by the dayside magnetopause are discussed. Attention is also given to changes of magnetic field line topology magnetic storms and substorms. Unresolved questions and new tools which may play a role in the further understanding of magnetospheric electrodynamics and the role of the magnetospheric electric field are presented.

  11. Inference of the angular velocity of plasma in the Jovian magnetosphere from the sweepback of magnetic field

    NASA Technical Reports Server (NTRS)

    Khurana, Krishan K.; Kivelson, Margaret G.

    1993-01-01

    The averaged angular velocity of plasma from magnetic observations is evaluated using plasma outflow rate as a parameter. New techniques are developed to calculate the normal and azimuthal components of the magnetic field in and near to the plasma sheet in a plasma sheet coordinate system. The revised field components differ substantially from the quantities used in previous analyses. With the revised field values, it appears that during the Voyager 2 flyby for an outflow rate of 2.5 x 10 exp 29 amu/s, the observed magnetic torque may be sufficient to keep the plasma in corotation to radial distances of 50 Rj in the postmidnight quadrant.

  12. Observations of magnetospheric substorms occurring with no apparent solar wind/IMF trigger

    SciTech Connect

    Henderson, M.G.; Reeves, G.D.; Belian, R.D.; Murphree, J.S.

    1996-03-01

    An outstanding topic in magnetospheric physics is whether substorms are always externally triggered by disturbances in either the interplanetary magnetic field or solar wind, or whether they can also occur solely as the result of an internal magnetospheric instability. Over the past decade, arguments have been made on both sides of this issue. Horwitz and McPherron have shown examples of substorm onsets which they claimed were not externally triggered. However, as pointed out by Lyons, there are several problems associated with these studies that make their results somewhat inconclusive. In particular, in the McPherron et al. study, fluctuations in the B{sub y} component were not considered as possible triggers. Furthermore, Lyons suggests that the sharp decreases in the AL index during intervals of steady IMF/solar wind, are not substorms at all but rather that they are just enhancements of the convection driven DP2 current system that are often observed to occur during steady magnetospheric convection events. In the present study, we utilize a much more comprehensive dataset (consisting of particle data from the Los Alamos energetic particle detectors at geosynchronous orbit, IMP 8 magnetometer and plasma data, Viking UV auroral imager data, mid-latitude Pi2 pulsation data, ground magnetometer data and ISEE1 magnetic field and energetic particle data) to show as unambiguously as possible that typical substorms can indeed occur in the absence of an identifiable trigger in the solar wind/IMF.

  13. Van Allen Probes Empirical Model of the Plasma Environment Inside Geostationary Orbit

    NASA Astrophysics Data System (ADS)

    Larsen, B.; Reeves, G. D.; Friedel, R. H. W.; Thomsen, M. F.; Skoug, R. M.; Funsten, H. O.; MacDonald, E.

    2014-12-01

    With the Van Allen probes nearing a full precession around the Earth we present a parameterized empirical model of the plasma properties in the inner magnetosphere. Data from the Los Alamos National Laboratory built Helium-Oxygen-Proton-Electron (HOPE) spectrometer on this this unparalleled two-satellite mission provides excellent coverage of the equatorial magnetosphere inside of geostationary, albeit over a limited range of geomagnetic activity. Fusing data and derived products from the two spacecraft a specification of the state of the inner magnetosphere has been created providing species resolved fluxes, partial densities, temperatures, anisotropies, and ratios. This full coverage model reproduces some well know phenomenology and presents some lesser know behaviors providing new insights into details of plasma dynamics inside geostationary orbit.

  14. Saturn's Periodic Magnetosphere: The Relation Between Periodic Hot Plasma Injections, a Rotating Partial Ring Current, Global Magnetic Field Distortions, Plasmapause Motion, and Radio Emissions

    NASA Astrophysics Data System (ADS)

    Brandt, P. C.; Mitchell, D. G.; Gurnett, D. A.; Persoon, A. M.; Tsyganenko, N. A.

    2012-04-01

    It has been know for some time that the large-scale energetic particle injections (~3-200 keV) on the nigh side of Saturn observed by Cassini/INCA are closely tracked by the periodic Saturn Kilometric Radiation (SKR). The resulting energetic particle pressure is comparable to that of the colder plasma and it therefore distorts the global magnetic field significantly as the energetic particle population drifts around Saturn. In this presentation we discuss the important consequences this has for the large-scale dynamics and configuration of the entire inner magnetosphere of Saturn. We begin by reviewing the observational correlations between remote, global INCA observations of energetic particles, magnetic field distortions, and radio emissions. We present examples of how the magnetic field measurements and the INCA observations show direct implications of a rotating 3D electrical current system associated with, not only, the energetic particle pressure, but also with an interhemispheric field-aligned current (FAC) system. Recently, we found an intriguing high correlation also between the periodic motion of the high-latitude plasmapause-like boundary reported by Gurnett et al. [2011] and the energetic particles observed remotely by INCA that are periodically injected on the night side and then drift around Saturn according to their energy. In our preliminary analysis we see a direct correlation in at least 75% of the case with the center of drifting energetic particle distribution [Brandt et al., 2010] and the encounter with the rotating plasmapause-like density boundary [Gurnett et al., 2011]. However, the remaining, low-correlation cases suggest that we do not fully understand the global, 3D current system that produces the periodic perturbations in Saturn's magnetosphere. We will use these observations to constrain the underlying 3D current system and in particular, assess the role of interhemispheric FACs in reproducing the observations.

  15. Near-horizon Kerr magnetosphere

    NASA Astrophysics Data System (ADS)

    Gralla, Samuel E.; Lupsasca, Alexandru; Strominger, Andrew

    2016-05-01

    We exploit the near-horizon conformal symmetry of rapidly spinning black holes to determine universal properties of their magnetospheres. Analytic expressions are derived for the limiting form of the magnetosphere in the near-horizon region. The symmetry is shown to imply that the black hole Meissner effect holds for free Maxwell fields but is generically violated for force-free fields. We further show that in the extremal limit, near-horizon plasma particles are infinitely boosted relative to accretion flow. Active galactic nuclei powered by rapidly spinning black holes are therefore natural sites for high-energy particle collisions.

  16. Los Alamos offers Fellowships

    NASA Astrophysics Data System (ADS)

    Los Alamos National Laboratory in New Mexico is calling for applications for postdoctoral appointments and research fellowships. The positions are available in geoscience as well as other scientific disciplines.The laboratory, which is operated by the University of California for the Department of Energy, awards J. Robert Oppenheimer Research Fellowships to scientists that either have or will soon complete doctoral degrees. The appointments are for two years, are renewable for a third year, and carry a stipend of $51,865 per year. Potential applicants should send a resume or employment application and a statement of research goals to Carol M. Rich, Div. 89, Human Resources Development Division, MS P290, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 by mid-November.

  17. Io's volcanism influences Jupiter's magnetosphere

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-02-01

    Volcanic emissions from Jupiter's moon Io supply plasma to the planet's magnetosphere and lead to its main auroral emissions. New observations show that the main auroral oval expanded and outer emissions brightened in spring 2007. Some studies have suggested that magnetospheric changes such as these could be caused by changes in the incoming solar wind. Bonfond et al. present several lines of evidence—including images from the Hubble Space Telescope and observations of a volcanic plume on Io from the New Horizons probe along with measurements of increased emissions from Jupiter's sodium cloud—that indicate that Io's volcanism controls changes in Jupiter's magnetosphere. (Geophysical Research Letters, doi:10.1029/2011GL050253, 2012)

  18. Energy limits of electron acceleration in the plasma sheet during substorms: A case study with the Magnetospheric Multiscale (MMS) mission

    SciTech Connect

    Turner, Drew Lawson; Fennell, J. F.; Blake, J. B.; Clemmons, J. H.; Mauk, B. H.; Cohen, I. J.; Jaynes, A. N.; Craft, J. V.; Wilder, F. D.; Baker, D. N.; Reeves, Geoffrey D.; Gershman, D. J.; Avanov, L. A.; Dorelli, J. C.; Giles, B. L.; Pollock, C. J.; Schmid, D.; Nakamura, R.; Strangeway, R. J.; Russell, C. T.; Artemyev, A. V.; Runov, A.; Angelopoulos, V.; Spence, H. E.; Torbert, R. B.; Burch, J. L.

    2016-08-01

    Here, we present multipoint observations of earthward moving dipolarization fronts and energetic particle injections from NASA's Magnetospheric Multiscale mission with a focus on electron acceleration. From a case study during a substorm on 02 August 2015, we find that electrons are only accelerated over a finite energy range, from a lower energy threshold at ~7–9 keV up to an upper energy cutoff in the hundreds of keV range. At energies lower than the threshold energy, electron fluxes decrease, potentially due to precipitation by strong parallel electrostatic wavefields or initial sources in the lobes. Electrons at energies higher than the threshold are accelerated cumulatively by a series of impulsive magnetic dipolarization events. This case demonstrates how the upper energy cutoff increases, in this case from ~130 keV to >500 keV, with each dipolarization/injection during sustained activity. We also present a simple model accounting for these energy limits that reveals that electron energization is dominated by betatron acceleration.

  19. Energy limits of electron acceleration in the plasma sheet during substorms: A case study with the Magnetospheric Multiscale (MMS) mission

    DOE PAGES

    Turner, Drew Lawson; Fennell, J. F.; Blake, J. B.; ...

    2016-08-01

    Here, we present multipoint observations of earthward moving dipolarization fronts and energetic particle injections from NASA's Magnetospheric Multiscale mission with a focus on electron acceleration. From a case study during a substorm on 02 August 2015, we find that electrons are only accelerated over a finite energy range, from a lower energy threshold at ~7–9 keV up to an upper energy cutoff in the hundreds of keV range. At energies lower than the threshold energy, electron fluxes decrease, potentially due to precipitation by strong parallel electrostatic wavefields or initial sources in the lobes. Electrons at energies higher than the thresholdmore » are accelerated cumulatively by a series of impulsive magnetic dipolarization events. This case demonstrates how the upper energy cutoff increases, in this case from ~130 keV to >500 keV, with each dipolarization/injection during sustained activity. We also present a simple model accounting for these energy limits that reveals that electron energization is dominated by betatron acceleration.« less

  20. Energy limits of electron acceleration in the plasma sheet during substorms: A case study with the Magnetospheric Multiscale (MMS) mission

    NASA Astrophysics Data System (ADS)

    Turner, D. L.; Fennell, J. F.; Blake, J. B.; Clemmons, J. H.; Mauk, B. H.; Cohen, I. J.; Jaynes, A. N.; Craft, J. V.; Wilder, F. D.; Baker, D. N.; Reeves, G. D.; Gershman, D. J.; Avanov, L. A.; Dorelli, J. C.; Giles, B. L.; Pollock, C. J.; Schmid, D.; Nakamura, R.; Strangeway, R. J.; Russell, C. T.; Artemyev, A. V.; Runov, A.; Angelopoulos, V.; Spence, H. E.; Torbert, R. B.; Burch, J. L.

    2016-08-01

    We present multipoint observations of earthward moving dipolarization fronts and energetic particle injections from NASA's Magnetospheric Multiscale mission with a focus on electron acceleration. From a case study during a substorm on 02 August 2015, we find that electrons are only accelerated over a finite energy range, from a lower energy threshold at 7-9 keV up to an upper energy cutoff in the hundreds of keV range. At energies lower than the threshold energy, electron fluxes decrease, potentially due to precipitation by strong parallel electrostatic wavefields or initial sources in the lobes. Electrons at energies higher than the threshold are accelerated cumulatively by a series of impulsive magnetic dipolarization events. This case demonstrates how the upper energy cutoff increases, in this case from 130 keV to >500 keV, with each dipolarization/injection during sustained activity. We also present a simple model accounting for these energy limits that reveals that electron energization is dominated by betatron acceleration.

  1. Relation Between Magnetospheric State Parameters and the Occurrence of Plasma Depletion Events in the Nighttime Midlatitude F Region

    NASA Technical Reports Server (NTRS)

    Seker, Ilgin; Fung, Shing F.; Mathews, John D.

    2011-01-01

    Studies using all-sky imagers have revealed the presence of various ionospheric irregularities in the nighttime midlatitude F region. The most prevalent and well known of these are the medium-scale traveling ionospheric disturbances (MSTIDs) that usually occur when the geomagnetic activity is low and midlatitude spread F plumes that are often observed when the geomagnetic activity is high. The inverse and direct relations between geomagnetic activity and the occurrence rate of MSTIDs and midlatitude plumes, respectively, have been observed by several studies using different instruments; however, most of them focus on MSTIDs only and use only Kp to characterize geomagnetic activity. In order to understand the underlying causes of these two relations and to distinguish between MSTIDs and plumes, it is illuminating to better characterize the occurrence of MSTIDs and plumes using multiple magnetospheric state parameters. Here we statistically compare multiple geomagnetic driver and response parameters (such as Kp, AE, Dst, and solar wind parameters) with the occurrence rates of nighttime MSTIDs and plumes observed using an all ]sky imager at Arecibo Observatory (AO) between 2003 and 2008. We also present seasonal and annual variations of MSTIDs and plumes at AO. The results not only allow us to better distinguish MSTIDs and plumes, but also to shed further light on the generation mechanism and electrodynamics of these two different phenomena occurring at nighttime in the midlatitude F region.

  2. Magnetospheric convection pattern and its implications

    NASA Technical Reports Server (NTRS)

    Zhu, Xiaoming

    1993-01-01

    When we use 14 months of the Fast Plasma Experiment ion velocity measurements, the mean magnetospheric circulation pattern is constructed. It is shown that the magnetospheric convection velocity is of the order tens of kilometers per second. The convection is largely restricted to the outer magnetosphere. During magnetically active periods the convection velocity increases and the convection boundary extends to the region closer to the Earth, indicating more magnetic field flux is being transported to the dayside magnetosphere. It is also shown that the convective flows tend to follow contours of constant unit flux volume as they move around the Earth, especially on the duskside of the magnetosphere. This helps to avoid the pressure balance inconsistency often found in two-dimensional magnetotail models.

  3. The Los Alamos primer

    SciTech Connect

    Serber, R.

    1992-01-01

    This book contains the 1943 lecture notes of Robert Serber. Serber was a protege of J. Robert Oppenheimer and member of the team that built the first atomic bomb - reveal what the Los Alamos scientists knew, and did not know, about the terrifying weapon they were building.

  4. Penetration of the interplanetary magnetic field B(sub y) magnetosheath plasma into the magnetosphere: Implications for the predominant magnetopause merging site

    NASA Technical Reports Server (NTRS)

    Newell, Patrick T.; Sibeck, David G.; Meng, Ching-I

    1995-01-01

    Magnetosheath plasma peertated into the magnetospere creating the particle cusp, and similarly the interplanetary magnetic field (IMF) B(sub y) component penetrates the magnetopause. We reexamine the phenomenology of such penetration to investigate implications for the magnetopause merging site. Three models are popular: (1) the 'antiparallel' model, in which merging occurs where the local magnetic shear is largest (usually high magnetic latitude); (2) a tilted merging line passing through the subsolar point but extending to very high latitudes; or (3) a tilted merging line passing through the subsolar point in which most merging occurs within a few Earth radii of the equatorial plane and local noon (subsolar merging). It is difficult to distinguish between the first two models, but the third implies some very different predictions. We show that properties of the particle cusp imply that plasma injection into the magnetosphere occurs most often at high magnetic latitudes. In particular, we note the following: (1) The altitude of the merging site inferred from midaltitude cusp ion pitch angle dispersion is typically 8-12 R(sub E). (2) The highest ion energy observable when moving poleward through the cusp drops long before the bulk of the cusp plasma is reached, implying that ions are swimming upstream against the sheath flow shortly after merging. (3) Low-energy ions are less able to enter the winter cusp than the summer cusp. (4) The local time behavior of the cusp as a function of B(sub y) and B(sub z) corroborates predictions of the high-latitude merging models. We also reconsider the penetration of the IMF B(sub y) component onto closed dayside field lines. Our approach, in which closed field lines ove to fill in flux voids created by asymmetric magnetopause flux erosion, shows that strich subsolar merging cannot account for the observations.

  5. Controlled Space Physics Experiments using Laboratory Magnetospheres

    NASA Astrophysics Data System (ADS)

    Mauel, M. E.; Kesner, J.; Garnier, D.

    2013-12-01

    Modern society's reliance on space-based platforms for a variety of economic and geopolitical purposes makes understanding the physics of the magnetosphere and "space weather'' one of the most important applications of plasma science. During the past decade, results from the CTX and LDX laboratory magnetospheres and from the RT-1 device at University of Tokyo, we have developed techniques to explore space physics using controlled experiments in laboratory magnetospheres. This presentation briefly reviews observations from the laboratory magnetospheres at Columbia University and MIT, including adiabatic drift-resonant transport, low-frequency MHD turbulence, and the formation of high-beta plasmas with profiles similar to Earth's inner magnetosphere. First principle validation of ``whole plasma'' space weather models have been completed in relevant magnetic geometry, including the spectrum and dynamics of turbulence successfully modeled with nonlinear bounce-averaged gyrokinetic simulations. Plans to explore Alfvénic dynamics and whistler wave trapping are discussed through the achievement of higher-density plasmas using radio-frequency heating. Photographs of the laboratory magnetospheres located at MIT (top) and Columbia University (bottom).

  6. Nitrogen In Saturn's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Smith, H. T.; Sittler, E. C.; Johnson, R. E.; McComas, D. J.; Reisenfeld, D.; Shappirio, M. D.; Baragiola, R.; Michael, M.; Shematovich, V. I.; Crary, F.; Young, D. T.

    2004-12-01

    We are analyzing CAPS instrument data on Cassini to look for nitrogen ions in Saturn's magnetosphere. Because Voyager could not separate oxygen and nitrogen, there has been considerable controversy on nitrogen's presence and relative importance. Two principal sources have been suggested: Titan's atmosphere and nitrogen species trapped in Saturn's icy satellite surfaces (Sittler et al 2004). The latter may be primordial nitrogen, likely as NH3 in ice (Stevenson 1982; Squyers et al. 1983) or nitrogen ions that have been implanted in the surface (Delitsky and Lane 2002). We will present the results of Saturnian nitrogen cloud modeling and relevant CAPS observations. We recently described the Titan source (Michael, et al. 2004; Shematovich et al. 2003; Smith et al. 2004; Sittler et al. 2004) in preparation for Cassini's Saturnian plasma measurements. Two components were identified: energetic nitrogen ions formed near Titan and energized as they diffused inward (Sittler et al. 2004) and neutrals in orbits with small perigee that became ionized in the inner magnetosphere (Smith et al 2004). The latter component would be a source of lower energy, co-rotating nitrogen ions in the inner magnetosphere. Such a component would have an energy spectrum similar to nitrogen species sputtered from the icy satellite surfaces (Johnson and Sittler 1990). However, the mass spectrum would differ, likely containing NHx and NOx species also, and, hence, may be separated from the Titan source. Our preliminary analysis for nitrogen species in the CAPS data will be compared to our models. Of interest will be the energy spectra, which can indicate whether any nitrogen present is formed locally or near Titan's orbit and diffused inward. This work is supported by the NASA Planetary Atmospheres, NASA Graduate Student Research, Virginia Space Grant Consortium Graduate Research Fellowship and CAPS Cassini instrument team programs.

  7. An overview of plasma wave observations obtained during the Galileo A34 pass through the inner region of the Jovian magnetosphere

    NASA Astrophysics Data System (ADS)

    Gurnett, D. A.; Kurth, W. S.; Menietti, J. D.; Roux, A.; Bolton, S. J.; Alexander, C. J.

    2003-04-01

    On November 5, 2002, the Galileo spacecraft, which is in orbit around Jupiter, made a pass in to a radial distance of 1.98 RJ (Jovian radii) from Jupiter, much closer than on any previous orbit. Data were successfully acquired during the entire inbound pass through the hot and cold plasma torii, and through the region inside the cold torus to a radial distance of 2.32 RJ, at which point the data system went into safing due to the intense radiation in the inner region of the magnetosphere. The purpose of this paper is to give an overview of the results obtained from the plasma wave investigation during this pass, which is designated A34. As on previous passes through the Io plasma torus a narrowband electrostatic emission at the upper hybrid resonance frequency provided a very accurate measurement of the electron density. The peak electron density, 2.6 x 103 cm-3, occurs just before the inner edge of the hot torus, which is at 5.62 RJ. As the spacecraft enters the cold torus the electron density drops to about 6.0 x 102 cm-3 and then gradually increases as the spacecraft approaches Jupiter, reaching a peak of about 2.5 x 103 cm-3 at 4.86 RJ, shortly before the inner edge of the cold torus. At the inner edge of the cold torus, which occurs at 4.76 RJ, the electron density drops dramatically to levels on the order of 1 cm-3. The electron density in this inner region is difficult to interpret because the upper hybrid emission can no longer be clearly identified, and there are numerous narrowband emissions with cutoffs that may or may not be associated with the local electron plasma frequency. As in the hot torus, the low density region inside the cold torus has a persistent level of plasma wave noise below about 103 Hz that is tentatively interpreted as whistler mode noise. The intensity of the whistler mode noise increases noticeably as the spacecraft crosses Thebe's orbit at 3.1 RJ, and increases markedly as the spacecraft crosses Amalthea's orbit at 2.6 RJ. The

  8. Hot proton anisotropies and cool proton temperatures in the outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Gary, S. Peter; Moldwin, Mark B.; Thomsen, Michelle F.; Winske, Dan; Mccomas, David J.

    1994-01-01

    The hot protons of the outer magnetosphere typically exhibit a temperature anistropy such that T(sub perp)/T(sub parallel) greater than 1, where perpendicular and parallel symbols denote directions relative to the background magnetic field. If this anisotrpy is sufficiently large, the electomagneitc proton cyclotron anistropy instability may be excited. This instability is studied using linear Vlasov theory and one-dimensional hybrid simulations for a homogeneous plasma model representative of conditions in the outer magnetosphere with a hot anisotropic proton component (denoted by subscript h) and a cool, initially isotropic proton component (subscript c). Linear theory yields an instability threshold condition on the hot proton temperature anistropy where as the simulations imply an upper bound on T(sub perp h)/T(sub parallel h); both the threshold and the upper bound have similar scaling with the maximum growth rate gamma (sub m), the parallel beta of the hot component, beta(sub parallel h), and the relative density of the hot component n(sub h)/n(sub e). An anlysis of plasma observations from the Los Alamos magnetospheric plasma analyzer (MPA) in geosynchronous orbits finds that the maximum value of the hot proton temperature anisotropy approximately satisfies the predicted scaling with beta(sub parallel h) and nu(sub h)/n(sub e) and yields the proportionality factor that quantifies this upper bound. The simulations are also used to examine the heating of the cool proton cyclotron instability. The simulations yield a scaling for the dimensionless late-time cool proton average temperature T(sub c)/T(sub parallel h) as (n(sub h)/n(sub e))/beta(sub parallel h exp 0.5). Analysis of MPA data shows that the observed values of T(sub c)/T(sub parallel h) have similar scaling and again yield the proportionality factor which quantifies this relationship.

  9. The protean magnetospheres of the solar system

    NASA Astrophysics Data System (ADS)

    Kivelson, Margaret G.

    2002-04-01

    Protean implies changeful, fluid, mobile, mutable, unsettled, unstable, unsteady, variable, or weathery according to the Merriam Webster Collegiate Thesaurus. All of these terms apply to the magnetospheres of the solar system. Comparative magnetospheric studies are becoming ever more rewarding as increasingly sophisticated and extensive spacecraft measurements reveal the versatility of plasma processes that control magnetospheric dynamics. Several aspects of these processes are particularly relevant to the extension of our knowledge from the local to the universal. The importance of the magnetic field for organization of structure and dynamics is dramatically illustrated even by simple models of magnetospheres of differing scales in different plasma regimes. Variations of the large scale structure are controlled by magnetic reconnection whose inner workings have been identified in a few events and by planetary rotation, a process that becomes dominant at Jupiter. Still poorly understood are the processes by which particles are accelerated to ultra-relativistic energies, although great progress is being made in this area.

  10. Does Enceladus govern magnetospheric dynamics at Saturn?

    PubMed

    Kivelson, Margaret Galland

    2006-03-10

    Instruments on the Cassini spacecraft reveal that a heat source within Saturn's moon Enceladus powers a great plume of water ice particles and dust grains, a geyser that jets outward from the south polar regions and most likely serves as the dominant source of Saturn's E ring. The interaction of flowing magnetospheric plasma with the plume modifies the particle and field environment of Enceladus. The structure of Saturn's magnetosphere, the extended region of space threaded by magnetic-field lines linked to the planet, is shaped by the ion source at Enceladus, and magnetospheric dynamics may be affected by the rate at which fresh ions are created.

  11. Simulations of Dynamic Relativistic Magnetospheres

    NASA Astrophysics Data System (ADS)

    Parfrey, Kyle Patrick

    Neutron stars and black holes are generally surrounded by magnetospheres of highly conducting plasma in which the magnetic flux density is so high that hydrodynamic forces are irrelevant. In this vanishing-inertia—or ultra-relativistic—limit, magnetohydrodynamics becomes force-free electrodynamics, a system of equations comprising only the magnetic and electric fields, and in which the plasma response is effected by a nonlinear current density term. In this dissertation I describe a new pseudospectral simulation code, designed for studying the dynamic magnetospheres of compact objects. A detailed description of the code and several numerical test problems are given. I first apply the code to the aligned rotator problem, in which a star with a dipole magnetic field is set rotating about its magnetic axis. The solution evolves to a steady state, which is nearly ideal and dissipationless everywhere except in a current sheet, or magnetic field discontinuity, at the equator, into which electromagnetic energy flows and is dissipated. Magnetars are believed to have twisted magnetospheres, due to internal magnetic evolution which deforms the crust, dragging the footpoints of external magnetic field lines. This twisting may be able to explain both magnetars' persistent hard X-ray emission and their energetic bursts and flares. Using the new code, I simulate the evolution of relativistic magnetospheres subjected to slow twisting through large angles. The field lines expand outward, forming a strong current layer; eventually the configuration loses equilibrium and a dynamic rearrangement occurs, involving large-scale rapid magnetic reconnection and dissipation of the free energy of the twisted magnetic field. When the star is rotating, the magnetospheric twisting leads to a large increase in the stellar spin-down rate, which may take place on the long twisting timescale or in brief explosive events, depending on where the twisting is applied and the history of the system

  12. Study of Static Microchannel Plate Saturation Effects for the Fast Plasma Investigation Dual Electron Spectrometers on NASA's Magnetospheric MultiScale Mission

    NASA Technical Reports Server (NTRS)

    Avanov, L. A.; Gliese, U.; Pollock, C. J.; Moore, T. E.; Chornay, D. J.; Barrie, A. C.; Kujawski, J. T.; Gershman, D. J.; Tucker, C. J.; Mariano, A.; Smith, D. L.; Jacques, A. D.

    2015-01-01

    Imaging detecting systems based on microchannel plates (MCPs) are the most common for low energy plasma measurements for both space borne and ground applications. One of the key parameters of these detection systems is the dynamic range of the MCP's response to the input fluxes of charged particles. For most applications the dynamic range of the linear response should be as wide as possible. This is especially true for the Dual Electron Spectrometers (DESs) of the Fast Plasma Investigation (FPI) on NASA's Magnetospheric MultiScale (MMS) mission because a wide range of input fluxes are expected. To make use of the full available dynamic range, it is important to understand the MCP response behavior beyond the linear regime where the MCPs start to saturate. We have performed extensive studies of this during the characterization and calibration of the DES instruments and have identified several saturation effects of the detection system. The MCP itself exhibits saturation when the channels lack the ability to replenish charge sufficiently rapidly. It is found and will be shown that the ground system can significantly impact the correct measurement of this effect. As the MCP starts to saturate, the resulting pulse height distribution (PHD) changes shape and location (with less pulse height values), which leads to truncation of the PHD by the threshold set on the detection system discriminator. Finally, the detection system pulse amplifier exhibits saturation as the input flux drives pulse rates greater than its linear response speed. All of these effects effectively change the dead time of the overall detection system and as a result can affect the quality and interpretation of the flight data. We present results of detection system saturation effects and their interaction with special emphasis on the MCP related effects.

  13. The Physics of the Laboratory Magnetosphere

    NASA Astrophysics Data System (ADS)

    Mauel, Michael

    2015-11-01

    During the past decade, experiments and simulations have characterized a new regime of high-beta toroidal plasma confinement using unique facilities, called laboratory magnetospheres. In a laboratory magnetosphere, a large plasma is confined by a relatively small, magnetically levitated, superconducting current ring. Nonlinear processes, including the inverse cascade of turbulent fluctuations and turbulent self-organization, are studied and controlled in near steady-state conditions. Because a dipole's magnetic field lines resemble the inner regions of planetary magnetospheres, these studies link laboratory and space plasma physics. However, unlike planetary magnetospheres, the magnetic field lines from a levitated dipole are axisymmetric and closed, imparting unique properties to the laboratory magnetosphere. A levitated dipole confines plasma without field-aligned currents, even when plasma pressure exceeds the local magnetic pressure (β > 1). Particle drifts are omnigeneous, and the dynamics of passing and trapped particles are similar. Because parallel currents can be a source for instability, many well-known low-frequency instabilities found in other toroidal configurations, like kink, tearing, ballooning, and drift modes, are not found in a dipole plasma torus. Instead, interchange and entropy modes, which resonate with bounce-averaged magnetic drifts, dominate plasma dynamics. This review emphasizes observations from the levitated dipole experiments at MIT and at the University of Tokyo, shows the application of gyrokinetic simulations and bounce-averaged fluid models with drift-kinetic closures to model the physics of the up-gradient turbulent pinch, describes the structure and chaotic dynamics of interchange and entropy mode instability, and introduces opportunities to apply the new physics of the laboratory magnetosphere to explore turbulent transport processes within a large quasi-steady magnetized plasma torus. Acknowledging contributions from Drs. D

  14. The Magnetospheric Constellation Mission (MC-DRACO)

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.

    2003-01-01

    The Magnetospheric Constellation Mission Dynamic Response and Coupling Observatory (MC-DRACO), the logical outgrowth of a sequence of STP missions, will explore plasma transport and energy conversion processes over a broad range of spatial sizes. Designed to be a meso-/macroscope for the magnetotail, it will resolve persistent controversies and yield a new understanding on which to build a predictive science of next generation magnetospheric meteorology.

  15. Magnetospheric Storms at Saturn and Earth

    NASA Astrophysics Data System (ADS)

    Brandt, P. C.; Mitchell, D. G.; Carbary, J.; Rymer, A.; Hill, M. E.; Paranicas, C.; Dougherty, M. K.; Young, D. T.

    2007-12-01

    The terrestrial magnetospheric storms are a well-known phenomenon in which plasma from the solar wind and the ionosphere is convected into the inner magnetosphere ("ring current") and energized by betatron acceleration and rapid changes in the magnetic field (substorms). Here we compare terrestrial storm characteristics with similar, newly found characteristics of Saturn's magnetosphere. We characterize Saturn's magnetospheric response to solar wind variability by using remote energetic neutral atom (ENA) measurements with simultaneous in-situ solar wind measurements when Cassini was outside the Saturnian magnetosphere. The Ion and Neutral Camera on board the Cassini spacecraft have obtained global energetic neutral atom (ENA) images of the hot plasma of Saturn's magnetosphere since February 2004. INCA obtains ENA images in the ~3-200 keV/nuc of protons and O+. The typical observations show hot plasma distributed roughly between 6 to 30 RS orbiting the planet with a period around the 10h45min rotation period depending on energy and species. However, some observations show how ENA intensity builds up on the nightside during intervals longer than the rotation period which indicates a gradual source of plasma. The intervals are often ended by a dramatic ENA intensification followed by a rotation of the newly injected plasma around the planet. We have selected a few of such intervals when Cassini was in the solar wind and could obtain solar wind parameters and simulataneous ENA image sequences. We use the Magnetic Field Experiment (MAG), the Cassini Charge Energy Mass Spectrometer (CHEMS), and the Cassini Plasma Spectrometer Subsystem (CAPS) to study the IMF, solar wind speed and density during these events and find that Saturn's magnetospheric activity most likely depends more on solar wind pressure than magnetic field orientation.

  16. Los Alamos Programming Models

    SciTech Connect

    Bergen, Benjamin Karl

    2016-07-07

    This is the PDF of a powerpoint presentation from a teleconference on Los Alamos programming models. It starts by listing their assumptions for the programming models and then details a hierarchical programming model at the System Level and Node Level. Then it details how to map this to their internal nomenclature. Finally, a list is given of what they are currently doing in this regard.

  17. Quantitative modelling of the electrostatic sheath around a photo-electron emitting spacecraft and of the possible influence on magnetospheric plasma instruments

    NASA Astrophysics Data System (ADS)

    Hilgers, A.; Thiebault, B.; Forest, J.; Escoubet, P.; Fehringer, M.; Laakso, H.

    2003-04-01

    It is well known that photo-electrons emitted from sunlit surfaces in space may affect plasma measurements by several processes, e.g., via the resulting (i) surface potential, (ii) space charge effects, or/and (iii) direct propagation to detectors [e.g. Szita et al., 2001; Pedersen et al., 1984]. We have used a fully kinetic particle-in-cell code, PicUp3D [Forest et al., 2001] which is now made available in public domain, for modelling in three dimensions the electrostatic sheath and photo-electron cloud around a conductive volume representative of a spacecraft like Cluster in a typical magnetospheric plasma environment. The model shows several features of key interest for the interpretation of the measurements and for optimizing the design of future instruments. It is found that photo-electrons fill a large volume around the spacecraft where they can dominate over the ambient environment and a significant part of photo-electrons propagates to the antisunward sector. The resulting space charge has been found to generate negative potential barriers under certain conditions. Also long wire booms which are generally used for mounting electrostatic sensors away from the influence of the spacecraft are found to induce significant transport of the spacecraft generated photo-electrons toward the boom mounted detectors. In this presentation the feature of the computer code and the results of the numerical model are reviewed and the implications for plasma instruments are discussed. Forest J., L. Eliasson, A. Hilgers, A New Spacecraft Plasma Simulation Software, PicUp3D/SPIS, ESA Special Publication, SP-476, ISBN No 92-9092-745-3, pp.515-520, ESA-ESTEC, Noordwijk, The Netherlands, 2001. Pedersen, A., C. A. Cattel, C.-G. Faelthammar, V. Formisano, P.-A. Lindqvist, F. Mozer, and R. Torbert, Quasistatic electric field measurements with spherical double probes on the GEOS and ISEE satellites, Space Sci. Rev., 37, pp 269-312, 1984. Szita, S., A. N. Fazakerley, P. J. Carter, A. M

  18. Dione's Magnetospheric Interaction

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Hospodarsky, G. B.; Schippers, P.; Moncuquet, M.; Lecacheux, A.; Crary, F. J.; Khurana, K. K.; Mitchell, D. G.

    2015-12-01

    Cassini has executed four close flybys of Dione during its mission at Saturn with one additional flyby planned as of this writing. The Radio and Plasma Wave Science (RPWS) instrument observed the plasma wave spectrum during each of the four encounters and plans to make additional observations during the 17 August 2015 flyby. These observations are joined by those from the Cassini Plasma Spectrometer (CAPS), Magnetospheric Imaging Instrument (MIMI), and the Magnetometer instrument (MAG), although neither CAPS nor MAG data were available for the fourth flyby. The first and fourth flybys were near polar passes while the second and third were near wake passes. The second flyby occurred during a time of hot plasma injections which are not thought to be specifically related to Dione. The Dione plasma wave environment is characterized by an intensification of the upper hybrid band and whistler mode chorus. The upper hybrid band shows frequency fluctuations with a period of order 1 minute that suggest density variations of up to 10%. These density variations are anti-correlated with the magnetic field magnitude, suggesting a mirror mode wave. Other than these periodic density fluctuations there appears to be no local plasma source which would be observed as a local enhancement in the density although variations in the electron distribution are apparent. Wake passages show a deep density depletion consistent with a plasma cavity downstream of the moon. Energetic particles show portions of the distribution apparently absorbed by the moon leading to anisotropies that likely drive both the intensification of the upper hybrid band as well as the whistler mode emissions. We investigate the role of electron anisotropies and enhanced hot electron fluxes in the intensification of the upper hybrid band and whistler mode emissions.

  19. A magnetospheric energy principle extended to include neutral atmosphere

    SciTech Connect

    Miura, Akira

    2011-03-15

    The problem of ideal magnetohydrodynamic stability of plasmas in a magnetosphere-atmosphere system, in which the unperturbed magnetic field is assumed to be perpendicular to the plasma-atmosphere interface (ionospheric surface), is investigated by means of an extended magnetospheric energy principle. The derivation of the principle and conditions under which it applies to a real terrestrial magnetosphere is given. In the principle, the atmosphere is considered to be a very heavy and compressible gas with finite pressure. A thin ionospheric layer is taken into account as boundary conditions, but energetics within it are neglected. The solid-earth surface is assumed to be a perfectly conducting wall for perturbations. For a perturbation that satisfies either rigid or horizontally free boundary conditions at the plasma-atmosphere interface, the self-adjointness of the force operator is satisfied and an extended magnetospheric energy principle can be developed on the basis of the extended energy principle for fusion plasmas. These two boundary conditions are shown to be realized in the magnetosphere when the ionospheric conductivity is either very large or very small. Whereas in fusion plasmas the perturbed magnetic energy in the vacuum makes a stabilizing contribution to the potential energy, in the magnetosphere the perturbed magnetic energy in the atmosphere makes no such stabilizing contribution. This is due to the difference of the assumed field configurations of the magnetospheric and fusion plasmas. The ionospheric surface makes a destabilizing negative contribution to the potential energy owing to a horizontal plasma displacement on the spherical ionospheric surface. The method is applied to magnetospheric ballooning and interchange instabilities. The existence of a new type of magnetospheric interchange instability is shown and its structure in the magnetosphere-atmosphere system is clarified. Possible consequences of the instabilities and their relevance to

  20. Analysis and visualization of global magnetospheric processes

    SciTech Connect

    Winske, D.; Mozer, F.S.; Roth, I.

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project is to develop new computational and visualization tools to analyze particle dynamics in the Earth`s magnetosphere. These tools allow the construction of a global picture of particle fluxes, which requires only a small number of in situ spacecraft measurements as input parameters. The methods developed in this project have led to a better understanding of particle dynamics in the Earth`s magnetotail in the presence of turbulent wave fields. They have also been used to demonstrate how large electromagnetic pulses in the solar wind can interact with the magnetosphere to increase the population of energetic particles and even form new radiation belts.

  1. Controlled Space Physics Experiments using Laboratory Magnetospheres

    NASA Astrophysics Data System (ADS)

    Mauel, Michael; Davis, M.; Garnier, D.; Roberts, T. M.; Worstell, M.; Kesner, J.

    2013-10-01

    Modern society's reliance on space-based platforms for a variety of economic and geopolitical purposes makes understanding the physics of the magnetosphere and ``space weather'' one of the most important applications of plasma science. During the past decade, results from the CTX and LDX laboratory magnetospheres and from the RT-1 device at University of Tokyo, we have developed techniques to explore space physics using controlled experiments in laboratory magnetospheres. This presentation briefly reviews observations from the laboratory magnetospheres at Columbia University and MIT, including adiabatic drift-resonant transport, low-frequency MHD turbulence, and the formation of high-beta plasmas with profiles similar to Earth's inner magnetosphere. First principle validation of ``whole plasma'' space weather models have been completed in relevant magnetic geometry, including the spectrum and dynamics of turbulence successfully modeled with nonlinear bounce-averaged gyrokinetic simulations. Plans to explore Alfvénic dynamics and whistler wave trapping are discussed through the achievement of higher-density plasmas using radio-frequency heating. Supported by the NSF-DOE Partnership in Plasma Science.

  2. On the convective properties of magnetospheric Bernstein waves

    NASA Technical Reports Server (NTRS)

    Barbosa, D. D.

    1980-01-01

    Recent plasma wave observations made by the ISEE and GEOS satellites of the electrostatic cyclotron harmonic waves have been consistent with and organized very well within the theoretical framework of Bernstein waves excited in magnetospheric plasma. Attention is given to an examination of a number of effects that result simply from the convective properties of Bernstein waves in a magnetospheric plasma environment. The roles of wave trapping in plasma density depressions and partial trappings near the magnetic equator are discussed. Certain future wave observations are suggested that can improve the understanding of this magnetospheric wave phenomenon.

  3. Transport processes in space plasmas

    SciTech Connect

    Birn, J.; Elphic, R.C.; Feldman, W.C.

    1997-08-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project represents a comprehensive research effort to study plasma and field transport processes relevant for solar-terrestrial interaction, involving the solar wind and imbedded magnetic field and plasma structures, the bow shock of the Earth`s magnetosphere and associated waves, the Earth`s magnetopause with imbedded flux rope structures and their connection with the Earth, plasma flow in the Earth`s magnetotail, and ionospheric beam/wave interactions. The focus of the work was on the interaction between plasma and magnetic and electric fields in the regions where different plasma populations exist adjacent to or superposed on each other. These are the regions of particularly dynamic plasma behavior, important for plasma and energy transport and rapid energy releases. The research addressed questions about how this interaction takes place, what waves, instabilities, and particle/field interactions are involved, how the penetration of plasma and energy through characteristic boundaries takes place, and how the characteristic properties of the plasmas and fields of the different populations influence each other on different spatial and temporal scales. These topics were investigated through combining efforts in the analysis of plasma and field data obtained through space missions with theory and computer simulations of the plasma behavior.

  4. Magnetospheric Substorm Electrodynamics

    NASA Technical Reports Server (NTRS)

    Lyons, L. R.

    1998-01-01

    It was proposed that the expansion phase of substorms results from a reduction in the large-scale electric field imparted to the magnetosphere from the solar wind, following a greater than or equal to 30 min growth phase due to an enhancement in this electric field. The reduction in the electric field is assumed to propagate anti-sunward within the magnetosphere. Triggering by a reduction in the electric field is suggested by the observation that substorms are often triggered by northward turning of the interplanetary magnetic field (IMF). However, under the theory presented here, substorms may be triggered by anything that causes an electric field reduction such as a reduction in the magnitude of the y-component of the IMF. A reduction in the large-scale electric field disrupts both the inward motion and energization of plasma sheet particles that occurs during the growth phase. It is suggested here that this can lead to formation of the expansion-phase current wedge and active aurora. The current wedge results from the magnetic drift of ions, which has a speed proportional to particle energy, and a large azimuthal gradient in mean particle energy that is expected to develop in the vicinity of magnetic midnight during the growth phase. Current wedge formation will most likely be initiated near the radial distance (approx. 6- 10 R(sub E)) of the peak in the growth-phase plasma pressure distribution, and then propagate tailward from that region. Order-of-magnitude calculations show that the above proposal can account for the rapid development of the expansion phase relative to the growth phase, the magnitude of the reduction in the cross-tail current within the current wedge, the speeds of tailward and westward expansion of the current reduction region, the speeds of poleward and westward motion of active aurora in the ionosphere, and the magnitude of wedge field-aligned currents that connect the ionospheric region of active auroral to the divergent cross

  5. Physics of magnetospheric boundary layers

    NASA Technical Reports Server (NTRS)

    Cairns, I. H.

    1993-01-01

    The central ideas of this grant are that the magnetospheric boundary layers link disparate regions of the magnetosphere together, and the global behavior of the magnetosphere can be understood only by understanding the linking mechanisms. Accordingly the present grant includes simultaneous research on the global, meso-, and micro-scale physics of the magnetosphere and its boundary layers. These boundary layers include the bow shock, magnetosheath, the plasma sheet boundary layer, and the ionosphere. Analytic, numerical and simulation projects have been performed on these subjects, as well as comparison of theoretical results with observational data. Very good progress has been made, with four papers published or in press and two additional papers submitted for publication during the six month period 1 June - 30 November 1993. At least two projects are currently being written up. In addition, members of the group have given papers at scientific meetings. The further structure of this report is as follows: section two contains brief accounts of research completed during the last six months, while section three describes the research projects intended for the grant's final period.

  6. Magnetospheric structures: Uranus and Neptune

    SciTech Connect

    Hill, T.W.

    1984-10-01

    Magnetospheric structures that might be encountered at Uranus and Neptune are described. Statistics indicate a sufficiently high probability to warrant consideration of their likely properties in advance of the Voyager encounters. Because the spin axis of Uranus lies nearly in the ecliptic and presently points approximately sunward, Voyager is likely to encounter the unique pole on configuration that has special theoretical significance. Corotation in the magnetospheres of Uranus and Neptune would probably exclude solar wind drive convection as an important driver of global magnetospheric dynamics, as it does at Jupiter and Saturn. The magnetospheres of Uranus and Neptune probably lack sufficient internal sources of plasma to produce significant levels of rotationally driven convection. The reported observation of auroral emission from Uranus has therefore motivated the development of an alternative model in which solar wind motion is coupled directly to the rotation of the ionosphere to establish a dynamo circuit which generates Birkeland currents and polar cap aurora. This model predicts the strength and configuration of the aurora as functions of the magnitude and polarity, respectively, of the planetary magnetic moment.

  7. Improved beta (local beta >1) and density in electron cyclotron resonance heating on the RT-1 magnetosphere plasma

    NASA Astrophysics Data System (ADS)

    Nishiura, M.; Yoshida, Z.; Saitoh, H.; Yano, Y.; Kawazura, Y.; Nogami, T.; Yamasaki, M.; Mushiake, T.; Kashyap, A.

    2015-05-01

    This study reports the recent progress in improved plasma parameters of the RT-1 device. Increased input power and the optimized polarization of electron cyclotron resonance heating (ECRH) with an 8.2 GHz klystron produce a significant increase in electron beta, which is evaluated by an equilibrium analysis of the Grad-Shafranov equation. The peak value of the local electron beta βe is found to exceed 1. In the high-beta and high-density regime, the density limit is observed for H, D and He plasmas. The line-averaged density is close to the cutoff density for 8.2 GHz ECRH. When the filling gas pressure is increased, the density limit still exists even in the low-beta region. This result indicates that the density limit is caused by the cutoff density rather than the beta limit. From the analysis of interferometer data, we found that inward diffusion causes a peaked density profile beyond the cutoff density.

  8. Multiple-satellite studies of magnetospheric substorms: Plasma sheet recovery and the poleward leap of auroral-zone activity

    NASA Technical Reports Server (NTRS)

    Pytte, T.; Mcpherron, R. L.; Kivelson, M. G.; West, H. I., Jr.; Hones, E. W., Jr.

    1977-01-01

    Particle observations from pairs of satellites (Ogo 5, Vela 4A and 5B, Imp 3) during the recovery of plasma sheet thickness late in substorms were examined. Six of the nine events occurred within about 5 min in locations near the estimated position of the neutral sheet, but over wide ranges of east-west and radial separations. The time of occurrence and spatial extent of the recovery were related to the onset (defined by ground Pi 2 pulsations) and approximate location (estimated from ground mid-latitude magnetic signatures) of substorm expansions. It was found that the plasma sheet recovery occurred 10 - 30 min after the last in a series of Pi bursts, which were interpreted to indicate that the recovery was not due directly to a late, high latitude substorm expansion. The recovery was also observed to occur after the substorm current wedge had moved into the evening sector and to extend far to the east of the center of the last preceding substorm expansion.

  9. A mechanism for magnetospheric substorms

    NASA Technical Reports Server (NTRS)

    Erickson, G. M.; Heinemann, M.

    1994-01-01

    Energy-principle analysis performed on two-dimensional, self-consistent solutions for magnetospheric convection indicates that the magnetosphere is unstable to isobaric (yet still frozen-in) fluctuations of plasma-sheet flux tubes. Normally, pdV work associated with compression maintains stability of the inward/outward oscillating normal mode. However, if Earth's ionosphere can provide sufficient mass flux, isobaric expansion of flux tubes can occur. The growth of a field-aligned potential drop in the near-Earth, midnight portion of the plasma sheet, associated with upward field-aligned currents responsible for the Harang discontinuity, redistributes plasma along field lines in a manner that destabilizes the normal mode. The growth of this unstable mode results in an out-of-equilibrium situation near the inner edge. When this occurs over a downtail extent comparable to the half-thickness of the plasma sheet, collapse ensues and forces thinning of the plasma sheet whereby conditions favorable to reconnection occur. This scenario for substorm onset is consistent with observed upward fluxes of ions, parallel potential drops, and observations of substorm onset. These observations include near Earth onset, pseudobreakups, the substorm current wedge, and local variations of plasma-sheet thickness.

  10. Magnetospheric convection in the nondipolar magnetic field of Uranus

    NASA Technical Reports Server (NTRS)

    Selesnick, Richard S.

    1988-01-01

    A method for determining the magnetospheric convection electric field, using simple analytic approximations under the assumption of uniform ionospheric conductivity, is described and applied to Uranus. Magnetic field models including quadrupole and octupole moments are used to determine the shape of the polar caps and the mapping of the electric field and parallel currents between ionosphere and magnetosphere. The model predictions are compared with plasma data taken by Voyager 2 in the inner Uranian magnetosphere.

  11. High Frequency Design Considerations for the Large Detector Number and Small Form Factor Dual Electron Spectrometer of the Fast Plasma Investigation on NASA's Magnetospheric Multiscale Mission

    NASA Technical Reports Server (NTRS)

    Kujawski, Joseph T.; Gliese, Ulrik B.; Cao, N. T.; Zeuch, M. A.; White, D.; Chornay, D. J; Lobell, J. V.; Avanov, L. A.; Barrie, A. C.; Mariano, A. J.; Tucker, C. J.; Piepgrass, B.; Auletti, C.; Weidner, S.; Jacques, A. D.; Pollock, C. J.

    2015-01-01

    Each half of the Dual Electron Spectrometer (DES) of the Fast Plasma Investigation (FPI) on NASA's Magnetospheric MultiScale (MMS) mission utilizes a microchannel plate Chevron stack feeding 16 separate detection channels each with a dedicated anode and amplifier/discriminator chip. The desire to detect events on a single channel with a temporal spacing of 100 ns and a fixed dead-time drove our decision to use an amplifier/discriminator with a very fast (GHz class) front end. Since the inherent frequency response of each pulse in the output of the DES microchannel plate system also has frequency components above a GHz, this produced a number of design constraints not normally expected in electronic systems operating at peak speeds of 10 MHz. Additional constraints are imposed by the geometry of the instrument requiring all 16 channels along with each anode and amplifier/discriminator to be packaged in a relatively small space. We developed an electrical model for board level interactions between the detector channels to allow us to design a board topology which gave us the best detection sensitivity and lowest channel to channel crosstalk. The amplifier/discriminator output was designed to prevent the outputs from one channel from producing triggers on the inputs of other channels. A number of Radio Frequency design techniques were then applied to prevent signals from other subsystems (e.g. the high voltage power supply, command and data handling board, and Ultraviolet stimulation for the MCP) from generating false events. These techniques enabled us to operate the board at its highest sensitivity when operated in isolation and at very high sensitivity when placed into the overall system.

  12. Magnetospheric plasma studies using data from the Dynamics Explorer high- and low-altitude plasma instruments. Final report, 15 April 1982-31 December 1985

    SciTech Connect

    Barfield, J.N.

    1986-02-01

    The reported research focused primarily upon plasma processes in and near the plasma cusp. The following areas were studied: plasma injection and transport in the mid-altitude polar cusp; observations of counterstreaming electrons at high altitudes; observations of upward electron beams and their relationship to region 1 Birkeland currents; observations of the electron population responsible for the 6300A SAR arc emission, polar rain observations; polar wind observations; and observations of ion and electron acceleration events produced by parallel electric fields. The primary observing platform for the research reported here was Dynamics Explorer 1 (DE-1). The DE-1 High Altitude Plasma Instrument (HAPI) consists of five electrostatic analyzers mounted in a fan-shaped angular array at angles of 45, 78, 90, 102, and 135/sup 0/. with respect to the spacecraft spin axis. Each analyzer makes differential measurements of electrons and positive ions over an energy/charge range of 5 eV/e to 32 keV/e. Energy stepping proceeds at commandable rates of up to 64 sec, providing three-dimensional plasma distribution functions at the six-second spin rate or DE-1.

  13. Corotation Lag in Jupiter's Magnetosphere: Comparison of Observation and Theory.

    PubMed

    Hill, T W

    1980-01-18

    Voyager 1 plasma flow data are compared with a recent theory that predicted measurable departures from rigid corotation in Jupiter's magnetosphere as a consequence of rapid plasma production and weak atmosphere-magnetosphere coupling. The comparison indicates that the theory can account for the observed corotation lag, provided that the plasma mass production rate during the Voyager 1 encounter was rather larger than expected, namely approximately 10(30) atomic mass units per second.

  14. Thermosphere-Ionosphere-Magnetosphere Coupling and Mass Outflow - the Magnetosphere/Ionosphere Perspective (Invited)

    NASA Astrophysics Data System (ADS)

    Wiltberger, M. J.

    2010-12-01

    Global scale models of the solar wind-magnetosphere-ionosphere interaction have long established history of including magnetosphere-ionosphere coupling through the electrodynamic coupling. Typically this coupling includes closure of field aligned currents from the magnetosphere in the electrostatic ionosphere with the conductances being modified by particle precipitation processes. Recent advances in simulation technology, namely multi-fluid MHD, allow the scope of MI coupling in simulations to include mass outflows from the thermosphere-ionosphere into the magnetosphere. Multiple approaches to addressing this challenge have been developed. In one approach empirical parametrization of the outflow characteristics, namely velocity and flux, are used to include high intensity sources such as the auroral zone and cusp. Another approach starts by modeling the plasma flow along a single field line and then expands to include multiple field lines convecting over the polar cap. In both approaches the ionospheric outflow has profound effects on the state of the magnetosphere. Generally speaking it improves agreement with Dst observations, alters the cross polar cap potential, and can fundamentally alter the evolution of the modeled magnetospheric state. Initial indications from some of the model efforts show that including this plasma source may also alter the solar wind-magnetosphere interaction. While significant advances on including these effects in global scale models has been accomplished many challenges remain.

  15. X-ray Probes of Magnetospheric Interactions with Jupiter's Auroral zones, the Galilean Satellites, and the Io Plasma Torus

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; Ramsey, B. D.; Waite, J. H., Jr.; Rehak, P.; Johnson, R. E.; Cooper, J. F.; Swartz, D. A.

    2004-01-01

    Remote observations with the Chandra X-ray Observatory and the XMM-Newton Observatory have shown that the Jovian system is a source of x-rays with a rich and complicated structure. The planet's polar auroral zones and its disk are powerful sources of x-ray emission. Chandra observations revealed x-ray emission from the Io Plasma Torus and from the Galilean moons Io, Europa, and possibly Ganymede. The emission from these moons is certainly due to bombardment of their surfaces of highly energetic protons, oxygen and sulfur ions from the region near the Torus exciting atoms in their surfaces and leading to fluorescent x-ray emission lines. Although the x-ray emission from the Galilean moons is faint when observed fiom Earth orbit, an imaging x-ray spectrometer in orbit around these moons, operating at 200 eV and above with 150 eV energy resolution, would provide a detailed mapping (down to 40 m spatial resolution) of the elemental composition in their surfaces. Here we describe the physical processes leading to x-ray emission fiom the surfaces of Jupiter's moons and the instrumental properties, as well as energetic ion flux models or measurements, required to map the elemental composition of their surfaces. We discuss the proposed scenarios leading to possible surface compositions. For Europa, the two most extreme are (1) a patina produced by exogenic processes such as meteoroid bombardment and ion implantation, and (2) upwelling of material fiom the subsurface ocean. We also describe the characteristics of X - m , an imaging x-ray spectrometer under going a feasibility study for the JIM0 mission, with the ultimate goal of providing unprecedented x-ray studies of the elemental composition of the surfaces of Jupiter's icy moons and Io, as well as of Jupiter's auroral x-ray emission.

  16. Saturn's dynamic magnetotail: A comprehensive magnetic field and plasma survey of plasmoids and traveling compression regions and their role in global magnetospheric dynamics

    NASA Astrophysics Data System (ADS)

    Jackman, C. M.; Slavin, J. A.; Kivelson, M. G.; Southwood, D. J.; Achilleos, N.; Thomsen, M. F.; DiBraccio, G. A.; Eastwood, J. P.; Freeman, M. P.; Dougherty, M. K.; Vogt, M. F.

    2014-07-01

    We present a comprehensive study of the magnetic field and plasma signatures of reconnection events observed with the Cassini spacecraft during the tail orbits of 2006. We examine their "local" properties in terms of magnetic field reconfiguration and changing plasma flows. We also describe the "global" impact of reconnection in terms of the contribution to mass loss, flux closure, and large-scale tail structure. The signatures of 69 plasmoids, 17 traveling compression regions (TCRs), and 13 planetward moving structures have been found. The direction of motion is inferred from the sign of the change in the Bθ component of the magnetic field in the first instance and confirmed through plasma flow data where available. The plasmoids are interpreted as detached structures, observed by the spacecraft tailward of the reconnection site, and the TCRs are interpreted as the effects of the draping and compression of lobe magnetic field lines around passing plasmoids. We focus on the analysis and interpretation of the tailward moving (south-to-north field change) plasmoids and TCRs in this work, considering the planetward moving signatures only from the point of view of understanding the reconnection x-line position and recurrence rates. We discuss the location spread of the observations, showing that where spacecraft coverage is symmetric about midnight, reconnection signatures are observed more frequently on the dawn flank than on the dusk flank. We show an example of a chain of two plasmoids and two TCRs over 3 hours and suggest that such a scenario is associated with a single-reconnection event, ejecting multiple successive plasmoids. Plasma data reveal that one of these plasmoids contains H+ at lower energy and W+ at higher energy, consistent with an inner magnetospheric source, and the total flow speed inside the plasmoid is estimated with an upper limit of 170 km/s. We probe the interior structure of plasmoids and find that the vast majority of examples at Saturn

  17. On the origin of turbulent cascades in the dynamic pressure and plasma flux from the discrete nonlinear ones: the role of outer magnetospheric resonances and their possible input into the trans-boundary transport.

    NASA Astrophysics Data System (ADS)

    Savin, Sergey; Büchner, Jörg; Zelenyi, Lev; Kronberg, Elena; Klimov, Stanislav; Kozak, Lyudmila; Blecki, Jan; Budaev, Viacheslav; Nemecek, Zdenek; Safrankova, Jana; Skalsky, Alexander; Amata, Ermanno

    The identification of the role of the Supersonic Plasma Streams (SPS) interactions with the Earth magnetosphere should be interesting in the context of the planetary and astrophysical magnetospheres and of that of laboratory plasmas. The interactions can be inherently non-local and non-equilibrium, and even explosive due to both solar wind (SW) induced and self-generated coherent structures in the multiscale system with the scales ranging from the micro to global scales. We study the main fundamental processes arising from the SPS cascading and interactions with surface and cavity resonances in the Earth’s magnetosphere, using multi-spacecraft data (SPECTR-R, DOUBLE STAR, CLUSTER, GEOTAIL, ACE, WIND etc.). We will address the following key problems to advance our understanding of anomalous transport and boundary dynamics: - the BS disturbances role in the SPS production; it requires to base on the relevant databases from the CLUSTER/ DOUBLE STAR/ GEOTAIL/SPECTR-R/ ACE/ WIND spacecraft, which will be used for a statistical analysis targeting the SPS statistical features as extreme events. - analysis of the SPS generation mechanisms, e.g., by bow shock (BS) surface or magnetosheath (MSH) cavity resonances, triggering by interplanetary shocks, solar wind (SW) dynamic pressure jumps, foreshock nonlinear structures, etc. - pumping of substantial part of the SW kinetic energy into the BS membrane and MSH cavity modes and initiate further cascades towards higher frequencies. Accordingly we present the multipoint studies of the SPS and of related nonlinear discrete cascades (carried generally by the SPS), along with the transformation of discrete cascades of the dynamic pressure into turbulent cascades. - explorations of spectral and bi-spectral cross-correlations in SW, foreshock, MSH and in vicinity of BS and magnetopause (MP) would demonstrate that both inflow and outflow into/ from magnetosphere can be modulated by the SPS and by the related outer magnetospheric

  18. Evidence for Corotating Convection in Saturn's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Kivelson, M. G.; Southwood, D. J.; Dougherty, M. K.

    2006-05-01

    Saturn's magnetic field exhibits a high degree of azimuthal symmetry, yet the field and plasma signatures of the magnetosphere are modulated at a period close to that of planetary rotation. How, then, is a clear periodicity imposed on the magnetic field and plasma of the planetary magnetosphere? In this talk, Cassini magnetometer data are used to develop a scenario for the dynamics of the Saturn magnetosphere. The proposal is that mass transport, accomplished in the inner magnetosphere by interchange motion, feeds into the outer magnetosphere where ballooning driven by centrifugal stress leads to outward transport, field reconnection and plasma loss in a favored local time sector; flux is transported inward in other regions. The model is closely related to the concept of corotating convection proposed by Dessler, Hill, and co-workers for Jupiter. The proposed mechanism can be consistent with aspects of the empirical camshaft model introduced by Espinosa et al., 2003 to explain Pioneer and Voyager magnetometer data. Anomalous transport here proposed could originate from a localized ionospheric conductivity anomaly. The resulting cyclic stress modulates the current in the current sheet and can account for its north-south excursions. The convection patterns proposed also imply that corotating, field-aligned currents would be a basic feature of the Saturn system.

  19. 3-D Force-balanced Magnetospheric Configurations

    SciTech Connect

    Sorin Zaharia; C.Z. Cheng; K. Maezawa

    2003-02-10

    The knowledge of plasma pressure is essential for many physics applications in the magnetosphere, such as computing magnetospheric currents and deriving magnetosphere-ionosphere coupling. A thorough knowledge of the 3-D pressure distribution has however eluded the community, as most in-situ pressure observations are either in the ionosphere or the equatorial region of the magnetosphere. With the assumption of pressure isotropy there have been attempts to obtain the pressure at different locations by either (a) mapping observed data (e.g., in the ionosphere) along the field lines of an empirical magnetospheric field model or (b) computing a pressure profile in the equatorial plane (in 2-D) or along the Sun-Earth axis (in 1-D) that is in force balance with the magnetic stresses of an empirical model. However, the pressure distributions obtained through these methods are not in force balance with the empirical magnetic field at all locations. In order to find a global 3-D plasma pressure distribution in force balance with the magnetospheric magnetic field, we have developed the MAG-3D code, that solves the 3-D force balance equation J x B = (upside-down delta) P computationally. Our calculation is performed in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials as B = (upside-down delta) psi x (upside-down delta) alpha. The pressure distribution, P = P(psi,alpha), is prescribed in the equatorial plane and is based on satellite measurements. In addition, computational boundary conditions for y surfaces are imposed using empirical field models. Our results provide 3-D distributions of magnetic field and plasma pressure as well as parallel and transverse currents for both quiet-time and disturbed magnetospheric conditions.

  20. Los Alamos National Laboratory

    SciTech Connect

    Dogliani, Harold O

    2011-01-19

    The purpose of the briefing is to describe general laboratory technical capabilities to be used for various groups such as military cadets or university faculty/students and post docs to recruit into a variety of Los Alamos programs. Discussed are: (1) development and application of high leverage science to enable effeictive, predictable and reliability outcomes; (2) deter, detect, characterize, reverse and prevent the proliferation of weapons of mass destruction and their use by adversaries and terrorists; (3) modeling and simulation to define complex processes, predict outcomes, and develop effective prevention, response, and remediation strategies; (4) energetic materials and hydrodynamic testing to develop materials for precise delivery of focused energy; (5) materials cience focused on fundamental understanding of materials behaviors, their quantum-molecular properties, and their dynamic responses, and (6) bio-science to rapidly detect and characterize pathogens, to develop vaccines and prophylactic remedies, and to develop attribution forensics.

  1. Global MHD Simulation of Mesoscale Structures at the Magnetospheric Boundary

    NASA Technical Reports Server (NTRS)

    Berchem, Jean

    1998-01-01

    The research carried out for this protocol was focused on the study of mesoscales structures at the magnetospheric boundary. We investigated three areas: (1) the structure of the magnetospheric boundary for steady solar wind conditions; (2) the dynamics of the dayside magnetospheric boundary and (3) the dynamics of the distant tail magnetospheric boundary. Our approach was to use high resolution three-dimensional global magnetohydrodynamic (MHD) simulations of the interaction of the solar wind with the Earth's magnetosphere. We first considered simple variations of the interplanetary conditions to obtain generic cases that helped us in establishing the basic cause and effect relationships for steady solar wind conditions. Subsequently, we used actual solar wind plasma and magnetic field parameters measured by an upstream spacecraft as input to the simulations and compared the simulation results with sequences of events observed by another or several other spacecraft located downstream the bow shock. In particular we compared results with observations made when spacecraft crossed the magnetospheric boundary.

  2. On the origin of low-energy electrons in the inner magnetosphere: Fluxes and pitch-angle distributions

    NASA Astrophysics Data System (ADS)

    Denton, M. H.; Reeves, G. D.; Larsen, B. A.; Friedel, R. F. W.; Thomsen, M. F.; Fernandes, P. A.; Skoug, R. M.; Funsten, H. O.; Sarno-Smith, L. K.

    2017-02-01

    Accurate knowledge of the plasma fluxes in the inner magnetosphere is essential for both scientific and programmatic applications. Knowledge of the low-energy electrons (approximately tens to hundreds of eV) in the inner magnetosphere is particularly important since these electrons are acted upon by various physical processes, accelerating the electrons to higher energies, and also causing their loss. However, measurements of low-energy electrons are challenging, and as a result, this population has been somewhat neglected previously. This study concerns observations of low-energy electrons made by the Helium Oxygen Proton Electron instrument on board the Van Allen Probes satellites and also observations from geosynchronous orbit made by the Magnetospheric Plasma Analyzer on board Los Alamos National Laboratory satellites. The fluxes of electrons from 30 eV to 1 keV are quantified as a function of pitch-angle, McIlwain L parameter, and local time for both quiet and active periods. Results indicate two sources for low-energy electrons in this energy range: the low-energy tail of the electron plasma sheet and the high-energy tail of the dayside ionosphere. These populations are identified primarily as a result of their different pitch-angle distributions. Field-aligned outflows from the dayside ionosphere are observed at all L shells during quiet and active periods. Our results also demonstrate that the dayside electron field-aligned fluxes at 30 eV are particularly strong between L values of 6 and 7, indicating an enhanced source within the polar ionosphere.

  3. The Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Burch, James

    Magnetospheric Multiscale (MMS), a NASA four-spacecraft mission scheduled for launch in November 2014, will investigate magnetic reconnection in the boundary regions of the Earth’s magnetosphere, particularly along its dayside boundary with the solar wind and the neutral sheet in the magnetic tail. Among the important questions about reconnection that will be addressed are the following: Under what conditions can magnetic-field energy be converted to plasma energy by the annihilation of magnetic field through reconnection? How does reconnection vary with time, and what factors influence its temporal behavior? What microscale processes are responsible for reconnection? What determines the rate of reconnection?
In order to accomplish its goals the MMS spacecraft must probe both those regions in which the magnetic fields are very nearly antiparallel and regions where a significant guide field exists. From previous missions we know the approximate speeds with which reconnection layers move through space to be from tens to hundreds of km/s. For electron skin depths of 5 to 10 km, the full 3D electron population (10 eV to above 20 keV) has to be sampled at rates greater than 10/s. The MMS Fast-Plasma Instrument (FPI) will sample electrons at greater than 30/s. Because the ion skin depth is larger, FPI will make full ion measurements at rates of greater than 6/s. 3D E-field measurements will be made by MMS once every ms. MMS will use an Active Spacecraft Potential Control device (ASPOC), which emits indium ions to neutralize the photoelectron current and keep the spacecraft from charging to more than +4 V. Because ion dynamics in Hall reconnection depend sensitively on ion mass, MMS includes a new-generation Hot Plasma Composition Analyzer (HPCA) that corrects problems with high proton fluxes that have prevented accurate ion-composition measurements near the dayside magnetospheric boundary. Finally, Energetic Particle Detector (EPD) measurements of electrons and

  4. Magnetospheric Multiscale (MMS) Orbit

    NASA Video Gallery

    This animation shows the orbits of Magnetospheric Multiscale (MMS) mission, a Solar-Terrestrial Probe mission comprising of four identically instrumented spacecraft that will study the Earth's magn...

  5. The relationship between the magnetosphere and magnetospheric/auroral substorms

    NASA Astrophysics Data System (ADS)

    Akasofu, S.-I.

    2013-03-01

    On the basis of auroral and polar magnetic substorm studies, the relationship between the solar wind-magnetosphere dynamo (the DD dynamo) current and the substorm dynamo (the UL dynamo) current is studied. The characteristics of both the DD and UL currents reveal why auroral substorms consist of the three distinct phases after the input power ɛ is increased above 1018 erg s-1. (a) The growth phase; the magnetosphere can accumulate magnetic energy for auroral substorms, when the ionosphere cannot dissipate the power before the expansion phase. (b) The expansion phase; the magnetosphere releases the accumulated magnetic energy during the growth phase in a pulse-like manner in a few hours, because it tries to stabilize itself when the accumulated energy reaches to about 1023 erg s-1. (c) The recovery phase; the magnetosphere becomes an ordinary dissipative system after the expansion phase, because the ionosphere becomes capable of dissipating the power with the rate of 1018 ~ 1019 erg s-1. On the basis of the above conclusion, it is suggested that the magnetosphere accomplishes the pulse-like release process (resulting in spectacular auroral activities) by producing plasma instabilities in the current sheet, thus reducing the current. The resulting contraction of the magnetic field lines (expending the accumulated magnetic energy), together with break down of the "frozen-in" field condition at distances of less than 10 RE, establishes the substorm dynamo that generates an earthward electric field (Lui and Kamide, 2003; Akasofu, 2011). It is this electric field which manifests as the expansion phase. A recent satellite observation at a distance of as close as 8.1 RE by Lui (2011) seems to support strongly the occurrence of the chain of processes suggested in the above. It is hoped that although the concept presented here is very crude, it will serve in providing one way of studying the three phases of auroral substorms. In turn, a better understanding of auroral

  6. Convection and Substorms - Paradigms of Magnetospheric Phenomenology

    NASA Astrophysics Data System (ADS)

    Kennel, Charles F.

    The magnetosphere is the region where cosmic rays and the solar wind interact with the Earth's magnetic field, creating such phenomena as the northern lights and other aurorae. The configuration and dynamics of the magnetosphere are of interest to planetary physicists, geophysicists, plasma astrophysicists, and to scientists planning space missions. The circulation of solar wind plasma in the magnetosphere and substorms have long been used as the principle paradigms for studying this vital region. Charles F. Kennel, a leading scientist in the field, here presents a synthesis of the convection and substorm literatures, and an analysis of convection and substorm interactions; he also suggests that the currently accepted steady reconnection model may be advantageously replaced by a model of multiple tail reconnection events, in which many mutually interdependent reconnections occur. Written in an accessible, non-mathematical style, this book introduces the reader to the exciting discoveries in this fast-growing field.

  7. Plasmasphere formation in arbitrarily oriented magnetospheres

    NASA Technical Reports Server (NTRS)

    Selesnick, R. S.; Richardson, J. D.

    1986-01-01

    The formation of plasmaspheres in planetary magnetospheres with arbitrary orientations of the rotation and magnetic dipole axes is investigated. A traditional plasmasphere with closed orbits inside the plasmapause and open trajectories outside it only occurs for the limiting case of aligned rotation and dipole axes. A time-variable plasmapause exists if the rotation axis is perpendicular to the solar win flow direction. In any other case, no definite plasmapause exists. Solar wind-driven convection transports plasma throughout the magnetosphere with an effectiveness which increases as the orientation goes further from one of the two limiting cases of strict plasmapause formation. The present analysis is applied to earth and Uranus using the actual orientations of the rotation and dipole axes. Particle trajectories at earth deviate only slightly from those obtained with traditional models. Uranus has no plasmasphere, and plasma convects sunwards throughout the inner magnetosphere.

  8. New Method for Accurate Calibration of Micro-Channel Plate based Detection Systems and its use in the Fast Plasma Investigation of NASA's Magnetospheric MultiScale Mission

    NASA Astrophysics Data System (ADS)

    Gliese, U.; Avanov, L. A.; Barrie, A.; Kujawski, J. T.; Mariano, A. J.; Tucker, C. J.; Chornay, D. J.; Cao, N. T.; Zeuch, M.; Pollock, C. J.; Jacques, A. D.

    2013-12-01

    The Fast Plasma Investigation (FPI) of the NASA Magnetospheric MultiScale (MMS) mission employs 16 Dual Electron Spectrometers (DESs) and 16 Dual Ion Spectrometers (DISs) with 4 of each type on each of 4 spacecraft to enable fast (30ms for electrons; 150ms for ions) and spatially differentiated measurements of full the 3D particle velocity distributions. This approach presents a new and challenging aspect to the calibration and operation of these instruments on ground and in flight. The response uniformity and reliability of their calibration and the approach to handling any temporal evolution of these calibrated characteristics all assume enhanced importance in this application, where we attempt to understand the meaning of particle distributions within the ion and electron diffusion regions. Traditionally, the micro-channel plate (MCP) based detection systems for electrostatic particle spectrometers have been calibrated by setting a fixed detection threshold and, subsequently, measuring a detection system count rate plateau curve to determine the MCP voltage that ensures the count rate has reached a constant value independent of further variation in the MCP voltage. This is achieved when most of the MCP pulse height distribution (PHD) is located at higher values (larger pulses) than the detection amplifier threshold. This method is adequate in single-channel detection systems and in multi-channel detection systems with very low crosstalk between channels. However, in dense multi-channel systems, it can be inadequate. Furthermore, it fails to fully and individually characterize each of the fundamental parameters of the detection system. We present a new detection system calibration method that enables accurate and repeatable measurement and calibration of MCP gain, MCP efficiency, signal loss due to variation in gain and efficiency, crosstalk from effects both above and below the MCP, noise margin, and stability margin in one single measurement. The fundamental

  9. Magnetospheric Substorms and Tail Dynamics

    NASA Technical Reports Server (NTRS)

    Hughes, W. Jeffrey

    1998-01-01

    This grant funded several studies of magnetospheric substorms and their effect on the dynamics of the earth's geomagnetic tail. We completed an extensive study of plasmoids, plasma/magnetic field structures that travel rapidly down the tail, using data from the ISEE 3 and IMP 8 spacecraft. This study formed the PhD thesis of Mark Moldwin. We found that magnetically plasmoids are better described as flux-ropes (twisted magnetic flux tubes) rather than plasma bubbles, as had been generally regarded up to that point (Moldwin and Hughes, 1990; 1991). We published several examples of plasmoids observed first in the near tail by IMP 8 and later in the distant tail by ISEE 3, confirming their velocities down tail. We showed how the passage of plasmoids distorts the plasma sheet. We completed the first extensive statistical survey of plasmoids that showed how plasmoids evolve as they move down tail from their formation around 30 RE to ISEE 3 apogee at 240 RE. We established a one-to-one correspondence between the observation of plasmoids in the distant tail and substorm onsets at earth or in the near tail. And we showed that there is a class of plasmoid-like structures that move slowly earthward, especially following weak substorms during northward IMF. Collectively this work constituted the most extensive study of plasmoids prior to the work that has now been done with the GEOTAIL spacecraft. Following our work on plasmoids, we turned our attention to signatures of substorm onset observed in the inner magnetosphere near geosynchronous orbit, especially signatures observed by the CRRES satellite. Using data from the magnetometer, electric field probe, plasma wave instrument, and low energy plasma instrument on CRRES we were able to better document substorm onsets in the inner magnetosphere than had been possible previously. Detailed calculation of the Poynting flux showed energy exchange between the magnetosphere and ionosphere, and a short burst of tailward convective

  10. Evidence for global electron transportation into the jovian inner magnetosphere.

    PubMed

    Yoshioka, K; Murakami, G; Yamazaki, A; Tsuchiya, F; Kimura, T; Kagitani, M; Sakanoi, T; Uemizu, K; Kasaba, Y; Yoshikawa, I; Fujimoto, M

    2014-09-26

    Jupiter's magnetosphere is a strong particle accelerator that contains ultrarelativistic electrons in its inner part. They are thought to be accelerated by whistler-mode waves excited by anisotropic hot electrons (>10 kiloelectron volts) injected from the outer magnetosphere. However, electron transportation in the inner magnetosphere is not well understood. By analyzing the extreme ultraviolet line emission from the inner magnetosphere, we show evidence for global inward transport of flux tubes containing hot plasma. High-spectral-resolution scanning observations of the Io plasma torus in the inner magnetosphere enable us to generate radial profiles of the hot electron fraction. It gradually decreases with decreasing radial distance, despite the short collisional time scale that should thermalize them rapidly. This indicates a fast and continuous resupply of hot electrons responsible for exciting the whistler-mode waves.

  11. Magnetospheric equilibrium with anisotropic pressure

    SciTech Connect

    Cheng, C.Z.

    1991-07-01

    Self-consistent magnetospheric equilibrium with anisotropic pressure is obtained by employing an iterative metric method for solving the inverse equilibrium equation in an optimal flux coordinate system. A method of determining plasma parallel and perpendicular pressures from either analytic particle distribution or particle distribution measured along the satellite's path is presented. The numerical results of axisymmetric magnetospheric equilibrium including the effects of finite beta, pressure anisotropy, and boundary conditions are presented for a bi-Maxwellian particle distribution. For the isotropic pressure cases, the finite beta effect produces an outward expansion of the constant magnetic flux surfaces in relation to the dipole field lines, and along the magnetic field the toroidal ring current is maximum at the magnetic equator. The effect of pressure anisotropy is found to further expand the flux surfaces outward. Along the magnetic field lines the westward ring current can be peak away from the equator due to an eastward current contribution resulting from pressure anisotropy. As pressure anisotropy increases, the peak westward current can become more singular. The outer boundary flux surface has significant effect on the magnetospheric equilibrium. For the outer flux boundary resembling dayside compressed flux surface due to solar wind pressure, the deformation of the magnetic field can be quite different from that for the outer flux boundary resembling the tail-like surface. 23 refs., 17 figs.

  12. Space physics: A fast lane in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Hudson, Mary K.

    2013-12-01

    A marriage between satellite observations and modelling has shown that acceleration of electrons in the magnetosphere can be explained by scattering of these particles by plasma oscillations known as chorus waves. See Letter p.411

  13. Experimental study of a mini-magnetosphere

    NASA Astrophysics Data System (ADS)

    Shaikhislamov, I. F.; Zakharov, Yu P.; Posukh, V. G.; Melekhov, A. V.; Antonov, V. M.; Boyarintsev, E. L.; Ponomarenko, A. G.

    2014-02-01

    Magnetospheres at ion kinetic scales, or mini-magnetospheres, possess unusual features as predicted by numerical simulations. However, there are practically no data on the subject from space observations and the data which are available are far too incomplete. In this paper we describe the results of a laboratory experiment on the interaction of plasma flow with a magnetic dipole with parameters such that the ion inertial length is larger than the size of an observed magnetosphere. A detailed structure of the non-coplanar or out-of-plane component of the magnetic field has been obtained in the meridian plane. The independence of this component on dipole moment reversal, as was reported in a previous work, has been verified. In the tail distinct lobes and a central current sheet have been observed. It was found that lobe regions adjacent to boundary layer are dominated by a non-coplanar component of magnetic field. Tail-ward oriented electric current in the plasma associated with that component appears to be equal to the ion current in the upstream part of magnetosphere and in the tail current sheet implying that electrons are stationary in those regions while the ions flow by. The data obtained strongly support the proposed model of mini-magnetosphere based on two-fluid effects as described by the Hall term.

  14. The current sheet in Jupiter's magnetosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1975-01-01

    A theoretical model is presented for the plasma in the Jovian magnetosphere whose pressure is comparable to the corotational energy density. The model predicts a thin current sheet of 1 Jupiter radius to 2 Jupiter radii half-thickness. The current sheet lies almost precisely in the magnetic equatorial plane and is not appreciably warped as suggested previously.

  15. Magnetosphere-ionosphere interactions

    NASA Technical Reports Server (NTRS)

    Vondrak, R. R.; Chiu, Y. T.; Evans, D. S.; Patterson, V. G.; Romick, G. J.; Stasiewicz, K.

    1979-01-01

    The present understanding of magnetosphere ionosphere interactions is described, and present and future predictive capabilities are assessed. Ionospheric features directly coupled to the magnetosphere to a significant degree are considered, with emphasis given to those phenomena of major interest to forecasters and users.

  16. Electron sources in Saturn's magnetosphere

    NASA Astrophysics Data System (ADS)

    Rymer, A. M.; Mauk, B. H.; Hill, T. W.; Paranicas, C.; André, N.; Sittler, E. C.; Mitchell, D. G.; Smith, H. T.; Johnson, R. E.; Coates, A. J.; Young, D. T.; Bolton, S. J.; Thomsen, M. F.; Dougherty, M. K.

    2007-02-01

    We investigate the sources of two different electron components in Saturn's inner magnetosphere (5 < L < 12 Rs) by performing phase space density (f(v)) analyses of electron measurements made by the Cassini CAPS instrument (1 eV to 28 keV). Because pitch angle distributions indicate that the traditional single particle invariants of gyration and bounce are not appropriate, we use a formulation of the isotropic invariant derived by Wolf (1983) and Schulz (1998) and show that it is similar in functional form to the first adiabatic invariant. Our f(v) analyses confirm that the cooler electrons (<100 eV) have a source in the inner magnetosphere and are likely products of neutral ionization processes in Saturn's neutral cloud. The mystery is how the electrons are heated to energies comparable to the proton thermal energy (which is approximately equal to the proton pickup energy), a process that reveals itself as a source of electrons at given invariant values in our f(v) analyses. We show that Coulomb collisions provide a viable mechanism to achieve the near equipartition of ion and electron energies in the time available before particles are lost from the region. We find that the source of the hotter electron component (>100 eV) is Saturn's middle or outer magnetosphere, perhaps transported to the inner magnetosphere by radial diffusion regulated by interchange-like injections. Hot electrons undergo heavy losses inside L ~ 6 and the distance to which the hot electron component penetrates into the neutral cloud is energy-dependent, with the coolest fraction of the hot plasma penetrating to the lowest L-shells. This can arise through energy-dependent radial transport during the interchange process and/or loss through the planetary loss cone.

  17. Auroral magnetosphere-ionosphere coupling: A brief topical review

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.; Schulz, M.; Cornwall, J. M.

    1979-01-01

    Auroral arcs result from the acceleration and precipitation of magnetospheric plasma in narrow regions characterized by strong electric fields both perpendicular and parallel to the earth's magnetic field. The various mechanisms that were proposed for the origin of such strong electric fields are often complementary Such mechanisms include: (1) electrostatic double layers; (2) double reverse shock; (3) anomalous resistivity; (4) magnetic mirroring of hot plasma; and (5) mapping of the magnetospheric-convection electric field through an auroral discontinuity.

  18. The Nonlinear Magnetosphere: Expressions in MHD and in Kinetic Models

    NASA Technical Reports Server (NTRS)

    Hesse, Michael; Birn, Joachim

    2011-01-01

    Like most plasma systems, the magnetosphere of the Earth is governed by nonlinear dynamic evolution equations. The impact of nonlinearities ranges from large scales, where overall dynamics features are exhibiting nonlinear behavior, to small scale, kinetic, processes, where nonlinear behavior governs, among others, energy conversion and dissipation. In this talk we present a select set of examples of such behavior, with a specific emphasis on how nonlinear effects manifest themselves in MHD and in kinetic models of magnetospheric plasma dynamics.

  19. Magnetosphere Environment from Solar System Planets/Moons to Exoplanets

    NASA Astrophysics Data System (ADS)

    Alexeev, Igor I.; Grygoryan, Maria S.; Belenkaya, Elena S.; Kalegaev, Vladimir V.; Khodachenko, Maxim

    First we discuss the solar wind plasma interaction with the Solar System planets that have intrinsic magnetic fields: Mercury, Earth, Jupiter, and Saturn are discussed. As a result of such an interaction cavities, which are free from the solar wind plasma and occupied by the planetary magnetic field are created. These cavities are usually called magnetospheres are surrounded and bound by the magnetopause. The magnetopause preserved the planetary magnetic field penetration into the magnetosheath so that its impossible for the magnetosheath plasma flow to penetrate into the magnetosphere. The magnetosheath are placed between the bow shock and the magnetopause. The bow shock forms a boundary against the unshocked super Alvénic plasma flow. As demonstrated by the analysis of the Mercury, Earth, Jupiter, and Saturn magnetopauses, these surfaces can be well described by a paraboloid of revolution with different subsolar distances and flaring angles. Based on this fact an universal model of the planetary magnetosphere can be constructed. We chose the planets in the inner magnetospheres of which the magnetic field vectors have been measured by orbiting spacecraft magnetometers. The proposed models describe the basic physical processes that are responsible for the structure and dynamics of the planetary magnetospheres. Additionally to the inner planetary field the different magnetospheric sources of magnetic field are included in the model. Finally, we discuss how these magnetosphere models can be applied to exoplanets in a comparative way.

  20. Modeling of Inner Magnetosphere Coupling Processes

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.

    2011-01-01

    The Ring Current (RC) is the biggest energy player in the inner magnetosphere. It is the source of free energy for Electromagnetic Ion Cyclotron (EMIC) wave excitation provided by a temperature anisotropy of RC ions, which develops naturally during inward E B convection from the plasmasheet. The cold plasmasphere, which is under the strong influence of the magnetospheric electric field, strongly mediates the RC-EMIC wave-particle-coupling process and ultimately becomes part of the particle and energy interplay. On the other hand, there is a strong influence of the RC on the inner magnetospheric electric and magnetic field configurations and these configurations, in turn, are important to RC dynamics. Therefore, one of the biggest needs for inner magnetospheric research is the continued progression toward a coupled, interconnected system with the inclusion of nonlinear feedback mechanisms between the plasma populations, the electric and magnetic fields, and plasma waves. As we clearly demonstrated in our studies, EMIC waves strongly interact with electrons and ions of energies ranging from approx.1 eV to approx.10 MeV, and that these waves strongly affect the dynamics of resonant RC ions, thermal electrons and ions, and the outer RB relativistic electrons. As we found, the rate of ion and electron scattering/heating in the Earth's magnetosphere is not only controlled by the wave intensity-spatial-temporal distribution but also strongly depends on the spectral distribution of the wave power. The latter is also a function of the plasmaspheric heavy ion content, and the plasma density and temperature distributions along the magnetic field lines. The above discussion places RC-EMIC wave coupling dynamics in context with inner magnetospheric coupling processes and, ultimately, relates RC studies with plasmaspheric and Superthermal Electrons formation processes as well as with outer RB physics.

  1. Theory of pulsar magnetosphere and wind

    NASA Astrophysics Data System (ADS)

    Pétri, Jérôme

    2016-10-01

    > leptons or does it contain a non-negligible fraction of protons and/or ions? Is it almost entirely filled or mostly empty except for some small anecdotal plasma filled regions? Answers to these questions will strongly direct the description of the magnetosphere to seemingly contradictory results leading sometimes to inconsistencies. Nevertheless, accounts are given as to the latest developments in the theory of pulsar magnetospheres and winds, the existence of a possible electrosphere and physical insight obtained from related observational signatures of multi-wavelength pulsed emission.

  2. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.

    2008-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. Mercury's magnetosphere is unique in many respects. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only - 1000 to 2000 km above the surface. For this reason there are no closed dri-fi paths for energetic particles and, hence, no radiation belts; the characteristic time scales for wave propagation and convective transport are short possibly coupling kinetic and fluid modes; magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere allowing solar wind ions to directly impact the dayside regolith; inductive currents in Mercury's interior should act to modify the solar In addition, Mercury's magnetosphere is the only one with its defining magnetic flux tubes rooted in a planetary regolith as opposed to an atmosphere with a conductive ionosphere. This lack of an ionosphere is thought to be the underlying reason for the brevity of the very intense, but short lived, approx. 1-2 min, substorm-like energetic particle events observed by Mariner 10 in Mercury's magnetic tail. In this seminar, we review what we think we know about Mercury's magnetosphere and describe the MESSENGER science team's strategy for obtaining answers to the outstanding science questions surrounding the interaction of the solar wind with Mercury and its small, but dynamic magnetosphere.

  3. Magnetospheres in the solar system

    SciTech Connect

    Mcnutt, R.L.

    1984-11-01

    Intrinsic and induced magnetospheres of planets, moons, and comets in the solar system are described. Magnetospheric electric fields, the plasmasphere, rotational effects, and corotation and convection dominated intrinsic magnetospheres are considered. Supersonic and subsonic interactions in induced magnetospheres are discussed. (ESA)

  4. Kinetic Framework for the Magnetosphere-Ionosphere-Plasmasphere-Polar Wind System: A UnifiedApproach for Studying Hot and Cold Plasma Interactions

    NASA Astrophysics Data System (ADS)

    Karimabadi, H.; Omelchenko, Y.; Schunk, R. W.; Barakat, A. R.; Gardner, L. C.; Khazanov, G. V.; Glocer, A.; Kistler, L. M.

    2013-12-01

    The Magnetosphere-Ionosphere-Plasmasphere-Polar Wind System is complex; it varies on a wide range in spatial and temporal scales, exhibits relatively thin ion-scale boundaries (e.g., bow shock, magnetopause, magnetotail), contains hot and cold particle populations, and the particle distribution functions are typically non-Maxwellian. The existing space weather frameworks are based on global fluid models and therefore cannot address many important issues concerning particle, momentum, and energy coupling in the system. To remedy this situation, we have formed a multi-disciplinary team to create a new kinetic modeling framework. The new framework will include kinetic electron and ion formulations for the ionosphere, plasmasphere, and polar wind domains, and kinetic ions and fluid electrons for the magnetosphere. The proposed methodology is expected to lead to breakthroughs in studying numerous problems/issues, including the self-consistent formation of the ring current, the self-consistent formation of ion scale turbulence and waves, the calculation of appropriate reconnection rates, the effect that multiple species and ion outflows from the ionosphere have on the development and evolution of storms/substorms, among others. The presentation will focus on the current state and capabilities of the global kinetic models that form the framework for the Magnetosphere-Ionosphere-Plasmasphere-Polar Wind Model.

  5. Heliospheric plasma sheet (HPS) impingement onto the magnetosphere as a cause of relativistic electron dropouts (REDs) via coherent EMIC wave scattering with possible consequences for climate change mechanisms

    NASA Astrophysics Data System (ADS)

    Tsurutani, B. T.; Hajra, R.; Tanimori, T.; Takada, A.; Bhanu, R.; Mannucci, A. J.; Lakhina, G. S.; Kozyra, J. U.; Shiokawa, K.; Lee, L. C.; Echer, E.; Reddy, R. V.; Gonzalez, W. D.

    2016-10-01

    A new scenario is presented for the cause of magnetospheric relativistic electron decreases (REDs) and potential effects in the atmosphere and on climate. High-density solar wind heliospheric plasmasheet (HPS) events impinge onto the magnetosphere, compressing it along with remnant noon-sector outer-zone magnetospheric 10-100 keV protons. The betatron accelerated protons generate coherent electromagnetic ion cyclotron (EMIC) waves through a temperature anisotropy (T⊥/T|| > 1) instability. The waves in turn interact with relativistic electrons and cause the rapid loss of these particles to a small region of the atmosphere. A peak total energy deposition of 3 × 1020 ergs is derived for the precipitating electrons. Maximum energy deposition and creation of electron-ion pairs at 30-50 km and at < 30 km altitude are quantified. We focus the readers' attention on the relevance of this present work to two climate change mechanisms. Wilcox et al. (1973) noted a correlation between solar wind heliospheric current sheet (HCS) crossings and high atmospheric vorticity centers at 300 mb altitude. Tinsley et al. has constructed a global circuit model which depends on particle precipitation into the atmosphere. Other possible scenarios potentially affecting weather/climate change are also discussed.

  6. Magnetospheric Image Unfolding

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Grant was a three year grant funded under the Space Physics Supporting Research and Technology and Suborbital Program. Our objective was to develop automated techniques needed to unfold or "invert" global images of the magnetospheric ion populations obtained by the new magnetospheric imaging techniques (ENA, EUV) in anticipation of future missions such as the Magnetospheric Imager and, now, IMAGE. Our focus on the present three year grant is to determine the degree to which such images can quantitatively constrain the global electromagnetic properties of the magnetosphere. In a previous three year grant period we successfully automated a forward modeling inversion algorithm, demonstrated that these inversions are robust in the face of realistic instrumental considerations such as counting statistics and backgrounds, applied error analysis techniques to the extracted parameters using variational procedures, implemented very realistic magnetospheric test images to test the inversion algorithms using the Rice University Magnetospheric Specification Model, and began the process of generating parametric models with the flexibility to handle the realistic magnetospheric images (e.g. Roelof et al, 1992; 1993). Our plan for the present 3 year grant period was to complete the development of the inversion tools needed to handle realistic magnetospheric images, assess the degree to which global electrodynamics is quantitatively constrained by ENA images of the magnetosphere, and bring the inversion of EUV images up to the maturity that we will have achieved for the ENA imaging. Below the accomplishments of our three year effort are present followed by a list of our presentations and publications. The accomplishments of all three years are presented here, and thus some of these items appeared on interim progress reports.

  7. A study of atmosphere-ionosphere-magnetosphere coupling

    NASA Technical Reports Server (NTRS)

    Raitt, W. J.; Paris, J. L.

    1982-01-01

    The properties of low energy plasma in the magnetosphere were predicted. The effects of wave particle interactions involving the concept of plasmons are studied, and quantum mechanical formulations are used for the processes occurring and bulk energization of the low energy plasma are investigated through the concept of the energy momentum tensor for the plasma and its electromagnetic environment.

  8. Information about Practicums at Los Alamos

    SciTech Connect

    Bradley, Paul A.

    2012-07-24

    The Los Alamos Neutron Science Center is the premier facility for neutron science experiments ranging from cross section measurements, neutron scattering experiments, proton radiography, cold neutrons, actinide neutronic properties, and many other exciting topics. The National High Magnetic Field Laboratory is home to several powerful magnets, including the one that created the first non-destructive 100 Tesla field in March 2012. They probe the electronic structure of superconductors, magnetic properties of materials (including magneto-quantum effects). Research is also conducted in correlated materials, thermoacoustics, and magnetic properties of actinides. The Trident Laser has a unique niche with very high power, short pulse experiments, with a peak power of 10{sup 20} W in short pulse mode. Discoveries range from production of monoenergetic MeV ion beam, nonlinear kinetic plasma waves, the transition between kinetic and fluid nonlinear behavior and other laser-plasma interaction processes.

  9. AB INITIO PULSAR MAGNETOSPHERE: THREE-DIMENSIONAL PARTICLE-IN-CELL SIMULATIONS OF AXISYMMETRIC PULSARS

    SciTech Connect

    Philippov, Alexander A.; Spitkovsky, Anatoly

    2014-04-20

    We perform ''first-principles'' relativistic particle-in-cell simulations of aligned pulsar magnetosphere. We allow free escape of particles from the surface of a neutron star and continuously populate the magnetosphere with neutral pair plasma to imitate pair production. As pair plasma supply increases, we observe the transition from a charge-separated ''electrosphere'' solution with trapped plasma and no spin-down to a solution close to the ideal force-free magnetosphere with electromagnetically dominated pulsar wind. We calculate the magnetospheric structure, current distribution, and spin-down power of the neutron star. We also discuss particle acceleration in the equatorial current sheet.

  10. An MHD model of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Wu, C. C.

    1985-01-01

    It is pointed out that the earth's magnetosphere arises from the interaction of the solar wind with the earth's geomagnetic field. A global magnetohydrodynamics (MHD) model of the earth's magnetosphere has drawn much attention in recent years. In this model, MHD equations are used to describe the solar wind interaction with the magnetosphere. In the present paper, some numerical aspects of the model are considered. Attention is given to the ideal MHD equations, an equation of state for the plasma, the model as an initial- and boundary-value problem, the shock capturing technique, computational requirements and techniques for global MHD modeling, a three-dimensional mesh system employed in the global MHD model, and some computational results.

  11. Evidence for particle acceleration during magnetospheric substorms

    NASA Technical Reports Server (NTRS)

    Lopez, Ramon E.; Baker, Daniel N.

    1994-01-01

    Magnetospheric substorms represent the episodic dissipation of energy stored in the geomagnetic tail that was previously extracted from the solar wind. This energy release produces activity throughout the entire magnetosphere-ionosphere system, and it results in a wide variety of phenomena such as auroral intensifications and the generation of new current systems. All of these phenomena involve the acceleration of particles, sometimes up to several MeV. We present a brief overview of substorm phenomenology. We then review some of the evidence for particle acceleration in Earth's magnetosphere during substorms. Such in-situ observations in this most accessible of all cosmic plasma domains may hold important clues to understanding acceleration processes in more distant astrophysical systems.

  12. Ion observations at Mercury's Magnetospheric Cusp

    NASA Astrophysics Data System (ADS)

    Jasinski, Jamie; Raines, Jim; Slavin, James

    2016-04-01

    The magnetospheric cusp is a region of direct entry for solar wind mass, energy and momentum into a planetary magnetosphere. Dayside magnetic reconnection between the interplanetary magnetic field and the planetary field allows shocked solar wind plasma to flow down open magnetospheric field lines. Whilst this is occurring these magnetic field lines convect poleward. For a spacecraft travelling through the high latitudes, this causes a velocity filter effect to be observed in the ion data, whereby higher energy ions are observed at lower latitudes. Here we present the ion observations from the MESSENGER spacecraft at Mercury's cusp, specifically focusing on ions latitudinally dispersed in energy. From these dispersions, the distance to the reconnection site is calculated and used to better understand the process of reconnection at Mercury's dayside magnetopause.

  13. Inner Magnetosphere Imager (IMI) instrument heritage

    NASA Technical Reports Server (NTRS)

    Wilson, G. R.

    1993-01-01

    This report documents the heritage of instrument concepts under consideration for the Inner Magnetosphere Imager (IMI) mission. The proposed IMI will obtain the first simultaneous images of the component regions of the inner magnetosphere and will enable scientists to relate these global images to internal and external influences as well as local observations. To obtain simultaneous images of component regions of the inner magnetosphere, measurements will be made of: (1) the ring current and inner plasma sheet using energetic neutral atoms; (2) the plasmasphere using extreme ultraviolet; (3) the electron and proton auroras using far ultraviolet and x rays; and (4) the geocorona using FUV. Instrument concepts that show heritage and traceability to those that will be required to meet the IMI measurement objectives are described.

  14. Inner Magnetosphere Imager (IMI) instrument heritage

    SciTech Connect

    Wilson, G.R.

    1993-03-01

    This report documents the heritage of instrument concepts under consideration for the Inner Magnetosphere Imager (IMI) mission. The proposed IMI will obtain the first simultaneous images of the component regions of the inner magnetosphere and will enable scientists to relate these global images to internal and external influences as well as local observations. To obtain simultaneous images of component regions of the inner magnetosphere, measurements will be made of: (1) the ring current and inner plasma sheet using energetic neutral atoms; (2) the plasmasphere using extreme ultraviolet; (3) the electron and proton auroras using far ultraviolet and x rays; and (4) the geocorona using FUV. Instrument concepts that show heritage and traceability to those that will be required to meet the IMI measurement objectives are described.

  15. How the Saturnian Magnetosphere Conserves Magnetic Flux

    NASA Astrophysics Data System (ADS)

    Powell, R. L.; Wei, H.; Russell, C. T.; Arridge, C. S.; Dougherty, M. K.

    2012-12-01

    The magnetospheric dynamics at Saturn are driven by the centrifugal force of near co-rotating water group ions released at a rate of hundreds of kilograms per second by Saturn's moon Enceladus. The plasma is accelerated up to co-rotation speed by the magnetospheric magnetic field coupled to the Saturnian ionosphere. The plasma is lost ultimately through the process of magnetic reconnection in the tail. Conservation of magnetic flux requires that plasma-depleted, "empty" flux tubes return magnetic flux to the inner magnetosphere. After completion of the initial inrush of the reconnected and largely emptied flux tubes inward of the reconnection point, the flux tubes face the outflowing plasma and must move inward against the flow. Observations of such flux tubes have been identified in the eight years of Cassini magnetometer data. The occurrence of these tubes is observed at all local times indicating slow inward transport of the tubes relative to the co-rotation speed. Depleted flux tubes observed in the equatorial region appear as an enhancement in the magnitude of the magnetic field, whereas the same flux tubes observed at higher latitudes appear as decreased field strength. The difference in appearance of the low latitude and the high latitude tubes is due to the plasma environment just outside the tube. Warm low-density plasma fills the inside of the flux tube at all latitudes. This flux tube thus will expand in the less dense regions away from the magnetic equator and will be observed as a decrease in the magnitude of the magnetic field from the background. These flux tubes near the equator, where the plasma density outside of the flux tube is much greater, will be observed as an enhancement in the magnitude of the magnetic field. Cassini magnetometer and CAPS data are examined to understand the properties of these flux tubes and their radial and latitudinal evolution throughout the Saturnian magnetospheric environment.

  16. Continuum radiation in planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.

    1991-01-01

    With the completion of the Voyager tour of the outer planets, radio and plasma wave instruments have executed the first survey of the wave spectra of Earth, Jupiter, Saturn, Uranus, and Neptune. One of the most notable conclusions of this survey is that there is a great deal of qualitative similarity in both the plasma wave and radio wave spectra from one magnetosphere to the next. In particular, in spite of detailed differences, most of the radio emissions at each of the planets have been tentatively classified into two primary categories. First, the most intense emissions are generally associated with the cyclotron maser instability. Second, a class of weaker emissions can be found at each of the magnetospheres which appears to be the result of conversion from intense electrostatic emissions at the upper hybrid resonance frequency into (primarily) ordinary mode radio emission. It is this second category, often referred to as nonthermal continuum radiation, which we will discuss in this review. We review the characteristics of the continuum spectrum at each of the planets, discuss the source region and direct observations of the generation of the emissions where available, and briefly describe the theories for the generation of the emissions. Over the past few years evidence has increased that the linear mode conversion of electrostatic waves into the ordinary mode can account for at least some of the continuum radiation observed. There is no definitive evidence which precludes the possibility that a nonlinear mechanism may also be important.

  17. Energetics of the magnetosphere, revised

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1984-01-01

    The approximate magnitudes of power inputs and energies associated with the Earth's magnetosphere were derived. The nearest 40 R sub E of the plasma sheet current receive some 3.10 to the 11th power watt, and much of this goes to the Birkeland currents, which require 1-3 10 to the 11th power watt. Of that energy, about 30% appears as the energy of auroral particles and most of the rest as ionosphere joule heating. The ring current contains about 10 to the 15th power joule at quiet times, several times as much during magnetic storms, and the magnetic energy stored in the tail lobes is comparable. Substorm energy releases may range at 1.5 to 30 10 to the 11th power watt. Compared to these, the local energy release rate by magnetic merging in the magnetosphere is small. Merging is essential for the existence of open field lines, which make such inputs possible. Merging also seems to be implicated in substorms: most of the released energy only becomes evident far from the merging region, though some particles may gain appreciable energy in that region itself, if the plasma sheet is squeezed out completely and the high latitude lobes interact directly.

  18. Titan Ion Composition at Magnetosphere-Ionosphere Transition Region

    NASA Technical Reports Server (NTRS)

    Sittler, Edward C.; Hartle, R. E.; Shappirio, M.; Simpson, D. J.; COoper, J. F.; Burger, M. H.; Johnson, R. E.; Bertucci, C.; Luhman, J. G.; Ledvina, S. A.; Szego, K.; Coates, A. J.; Young, D. T.

    2006-01-01

    Using Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS) ion composition data, we will investigate the compositional changes at the transition region between Saturn's magnetospheric flow and Titan's upper ionosphere. It is this region where scavenging of Titan's upper ionosphere can occur, where it is then dragged away by the magnetospheric flow as cold plasma for Saturn's magnetosphere. This cold plasma may form plumes as originally proposed by (1) during the Voyager 1 epoch. This source of cold plasma may have a unique compositional signature such as methane group ions. Water group ions that are observed in Saturn's outer magnetosphere (2,3) are relatively hot and probably come from the inner magnetosphere where they are born from fast neutrals escaping Enceladus (4) and picked up in the outer magnetosphere as hot plasma (5). This scenario will be complicated by pickup methane ions within Titan's mass loading region, as originally predicted by (6) based on Voyager 1 data and observationally confirmed by (3,7) using CAPS IMS data. But, CH4(+) ions or their fragments can only be produced as pickup ions from Titan's exosphere which can extend beyond the transition region of concern here, while CH5(+) ions can be scavenged from Titan's ionosphere. We will investigate these possibilities.

  19. Laboratory study of mini-magnetosphere

    NASA Astrophysics Data System (ADS)

    Shaikhislamov, Ildar; Zakharov, Yuri; Posukh, Vitaly; Melekhov, Aleksandr; Antonov, Vladimir; Boyarintsev, Eduard; Ponomarenko, Arnold

    Laboratory study of mini-magnetosphere Magnetosphere at ion kinetic scales, or mini-magnetosphere, which is observed above lunar magnetic anomalies or might be discovered around magnetized asteroids in future missions, possesses unusual features as predicted by numerical simulations. However, there are practically no data on the subject from space observations and the data which is available is far too incomplete. In the present work we describe results of laboratory experiment on interaction of plasma flow with magnetic dipole with parameters such that ion inertia length is smaller than a size of observed magnetosphere. A detailed structure of non-coplanar or out-of-plane component of magnetic field has been obtained in meridian plane. Independence of this component on dipole moment reversal, as was reported in previous works (Shaikhislamov et al 2013, 2014), has been verified. In the tail distinct lobes and central current sheet have been observed. It was found that lobe regions adjacent to boundary layer are dominated by non-coplanar component of magnetic field. Tail-ward oriented electric current in plasma associated with that component appears to be equal to ion current in the frontal part of magnetosphere and in the tail current sheet implying that electrons are stationary in those regions while ions flow by. Obtained data strongly support the proposed model of mini-magnetosphere based on two-fluid effects as described by the Hall term and suggest that spacecraft crossing the tail of magnetized asteroid might observe, instead of simple reversion of tail-ward field, a complex 3-D rotation of magnetic field vector. Acknowledgements This work was supported by SB RAS Research Program grant II.8.1.4, Russian Fund for Basic Research grant 12-02-00367, OFN RAS Research Program 15 and Presidium RAS Research Program 22. References Shaikhislamov, I. F., Antonov, V. M., Zakharov, Yu. P., Boyarintsev, E. L., Melekhov, A. V., Posukh, V. G. and Ponomarenko, A. G. Mini-magnetosphere

  20. The Magnetosphere Imager Mission Concept Definition Study

    NASA Technical Reports Server (NTRS)

    Johnson, L.; Herrmann, M.; Alexander, Reggie; Beabout, Brent; Blevins, Harold; Bridge, Scott; Burruss, Glenda; Buzbee, Tom; Carrington, Connie; Chandler, Holly; Chu, Phillip; Chubb, Steve; Cushman, Paul; DeSanctis, Carmine; Edge, Ted; Freestone, Todd; French, Ray; Gallagher, Dennis; Hajos, Greg; Herr, Joel

    1997-01-01

    For three decades, magnetospheric field and plasma measurements have been made by diverse instruments flown on spacecraft in many different orbits, widely separated in space and time, and under various solar and magnetospheric conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the magnetosphere. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data and help explain complex magnetospheric processes, thus providing us with a clear picture of this region of space. The George C. Marshall Space Flight Center (MSFC) is responsible for defining the Magnetosphere Imager mission which will study this region of space. A core instrument complement of three imagers (with the potential addition of one or more mission enhancing instrument) will fly in an elliptical polar Earth orbit with an apogee of 44,600 kilometers and a perigee of 4,800 km. This report will address the mission objectives, spacecraft design concepts, and the results of the MSFC concept definition study.

  1. Quantitative magnetospheric models: results and perspectives.

    NASA Astrophysics Data System (ADS)

    Kuznetsova, M.; Hesse, M.; Gombosi, T.; Csem Team

    Global magnetospheric models are indispensable tool that allow multi-point measurements to be put into global context Significant progress is achieved in global MHD modeling of magnetosphere structure and dynamics Medium resolution simulations confirm general topological pictures suggested by Dungey State of the art global models with adaptive grids allow performing simulations with highly resolved magnetopause and magnetotail current sheet Advanced high-resolution models are capable to reproduced transient phenomena such as FTEs associated with formation of flux ropes or plasma bubbles embedded into magnetopause and demonstrate generation of vortices at magnetospheric flanks On the other hand there is still controversy about the global state of the magnetosphere predicted by MHD models to the point of questioning the length of the magnetotail and the location of the reconnection sites within it For example for steady southwards IMF driving condition resistive MHD simulations produce steady configuration with almost stationary near-earth neutral line While there are plenty of observational evidences of periodic loading unloading cycle during long periods of southward IMF Successes and challenges in global modeling of magnetispheric dynamics will be addessed One of the major challenges is to quantify the interaction between large-scale global magnetospheric dynamics and microphysical processes in diffusion regions near reconnection sites Possible solutions to controversies will be discussed

  2. Multiscale phenomena in the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Surjalal Sharma, A.

    The multiscale phenomena in the Earth's magnetosphere have been studied using data from ground-based and space-borne measurements. The ground-based observations provide data over decades and are suitable for characterizing the inherent nature of the multiscale behavior and for studying the dynamical and statistical features. On the other hand, the spacecraft data provide in-situ observations of the processes. The multipoint measurements by Cluster have provided a new understanding of the plasma processes at microand meso-scales and the cross-scale coupling among them. The role of cross-scale coupling is evident in phenomena such as bursty bulk flows, flux ropes, and reconnection. The characteristic scales of the processes range from electron skin depth to MHD scales and the modeling of these processes need different physical models, such as kinetic, EMHD, Hall MHD, and MHD. The ground-based data have been used to develop models based on techniques of nonlinear science and yield predictive models which can be used for forecasting. These models characterize the magnetospheric dynaics and yield its global and multiscale aspects. The distribution of scales in the magnetosphere is studied using an extensive database of the solar wind and the magnetosphere. The distributions of the waiting times deviate significantly from a power law as well as stretched exponential distributions, and show a scaling with respect to the mean, indicating a limited role of long-term correlations in the magnetospheric dynamics.

  3. Solar and magnetospheric science

    NASA Technical Reports Server (NTRS)

    Timothy, A. F.; Schmerling, E. R.; Chapman, R. D.

    1976-01-01

    The current status of the Solar Physics Program and the Magnetospheric Physics Program is discussed. The scientific context for each of the programs is presented, then the current programs and future plans are outlined.

  4. Laboratory simulation of magnetospheric chorus wave generation

    NASA Astrophysics Data System (ADS)

    Van Compernolle, B.; An, X.; Bortnik, J.; Thorne, R. M.; Pribyl, P.; Gekelman, W.

    2017-01-01

    Whistler mode chorus emissions with a characteristic frequency chirp are important magnetospheric waves, responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. A laboratory experiment (Van Compernolle et al 2015 Phys. Rev. Lett. 114 245002, An et al 2016 Geophys. Res. Lett.) in the large plasma device at UCLA was designed to closely mimic the scaled plasma parameters observed in the inner magnetosphere, and shed light on the excitation of discrete frequency whistler waves. It was observed that a rich variety of whistler wave emissions is excited by a gyrating electron beam. The properties of the whistler emissions depend strongly on plasma density, beam density and magnetic field profiles.

  5. Planetary Magnetosphere Probed by Charged Dust Particles

    NASA Astrophysics Data System (ADS)

    Sternovsky, Z.; Horanyi, M.; Gruen, E.; Srama, R.; Auer, S.; Kempf, S.; Krueger, H.

    2010-12-01

    In-situ and remote sensing observations combined with theoretical and numerical modeling greatly advanced our understanding planetary magnetospheres. Dust is an integral component of the Saturnian and Jovian magnetospheres where it can act as a source/sink of plasma particles (dust particles are an effective source for plasma species like O2, OH, etc. through sputtering of ice particles, for example); its distribution is shaped by electrodynamic forces coupled radiation pressure, plasma, and neutral drag, for example. The complex interaction can lead to unusual dust dynamics, including the transport, capture, and ejection of dust grains. The study of the temporal and spatial evolution of fine dust within or outside the magnetosphere thus provides a unique way to combine data from a large number of observations: plasma, plasma wave, dust, and magnetic field measurements. The dust detectors on board the Galileo and Cassini spacecrafts lead to major discoveries, including the jovian dust stream originating from Io or the in-situ sampling and analysis of the plumes of Enceladus. Recent advancement in dust detector technology enables accurate measurement of the dust trajectory and elemental composition that can greatly enhance the understanding of dust magnetorspheric interaction and indentify the source of the dust with high precision. The capabilities of a modern dust detector thus can provide support for the upcoming Europa Jupiter System Mission.

  6. Composition measurements in the dusk flank magnetosphere

    NASA Astrophysics Data System (ADS)

    Fuselier, S. A.; Elphic, R. C.; Gosling, J. T.

    1999-03-01

    The dusk flank magnetosphere exhibits significant structure. Several regions have been identified, including the plasma sheet, mantle, and low latitude boundary layer. Transitions from one region to the next, for example from the mantle to the plasma sheet, can be abrupt or indistinct. In addition, the density within the flank mantle can range over several orders of magnitude. Although there is significant structure in this region of the magnetosphere, individual regions often can be distinguished by their energy spectra and ion composition. ISEE Fast Plasma Experiment and Plasma Composition Experiment data are used to examine the composition of the mantle and to study a set of transitions from the mantle to the plasma sheet where plasmas with mantle-like and plasma sheet-like energies mix. This study indicates that the variability of the mantle density is largely due to variability in the solar wind component (H+ and He2+); the ionospheric plasma (O+) density is roughly constant. Similarly, the plasma with mantle-like energy found in the mixed region is largely of solar wind origin.

  7. A magnetohydrodynamic model of the interaction of the solar wind with the Jovian magnetosphere and a magnetohydrodynamic simulation of the interaction of the solar wind with the out flowing plasma from a comet

    NASA Technical Reports Server (NTRS)

    Walker, R. J.

    1987-01-01

    A three-dimensional code for a rapidly rotating magnetosphere in which the MHD equations and the Maxwell equations were solved by using the two step Lax Endroff scheme, was developed. Preliminary results were presented at the Fall AGU meeting in San Francisco. The basic simulation model to study the solar wind interactions was adapted to other bodies in addition to Jupiter. Because of the recent comet flybys, a comet was chosen as the first model. The aim was to model the formation of the contact surface and the plasma tail. Later, work was begun on a three-dimensional model which would include the effects of mass loading. This model was designed to study the weak cometary bow shocks observed by the probes to comets Halley and Giacobini-Zinner. The model was successful in reproducing the position and shape of the bow shock which was determined by using observations from the Suisei spacecraft.

  8. Multi-Scale Modeling of Magnetospheric Dynamics

    NASA Technical Reports Server (NTRS)

    Kuznetsova, M. M.; Hesse, M.; Toth, G.

    2012-01-01

    Magnetic reconnection is a key element in many phenomena in space plasma, e.g. Coronal mass Ejections, Magnetosphere substorms. One of the major challenges in modeling the dynamics of large-scale systems involving magnetic reconnection is to quantifY the interaction between global evolution of the magnetosphere and microphysical kinetic processes in diffusion regions near reconnection sites. Recent advances in small-scale kinetic modeling of magnetic reconnection significantly improved our understanding of physical mechanisms controlling the dissipation in the vicinity of the reconnection site in collisionless plasma. However the progress in studies of small-scale geometries was not very helpful for large scale simulations. Global magnetosphere simulations usually include non-ideal processes in terms of numerical dissipation and/or ad hoc anomalous resistivity. Comparative studies of magnetic reconnection in small scale geometries demonstrated that MHD simulations that included non-ideal processes in terms of a resistive term 11 J did not produce fast reconnection rates observed in kinetic simulations. In collisionless magnetospheric plasma, the primary mechanism controlling the dissipation in the vicinity of the reconnection site is nongyrotropic pressure effects with spatial scales comparable with the particle Larmor radius. We utilize the global MHD code BATSRUS and replace ad hoc parameters such as "critical current density" and "anomalous resistivity" with a physically motivated model of dissipation. The primary mechanism controlling the dissipation in the vicinity of the reconnection site in incorporated into MHD description in terms of non-gyrotropic corrections to the induction equation. We will demonstrate that kinetic nongyrotropic effects can significantly alter the global magnetosphere evolution. Our approach allowed for the first time to model loading/unloading cycle in response to steady southward IMF driving. The role of solar wind parameters and

  9. Mercury's Dynamic Magnetosphere: What Have We Learned from MESSENGER?

    NASA Astrophysics Data System (ADS)

    Slavin, James A.

    2016-04-01

    Mercury's magnetosphere is created by the solar wind interaction with its dipolar, spin-axis aligned, northward offset intrinsic magnetic field. Structurally it resembles that of the Earth in many respects, but the magnetic field intensities and plasma densities are all higher at Mercury due to conditions in the inner solar system. Magnetospheric plasma at Mercury appears to be primarily of solar wind origin, i.e. H+ and He++, but with 10% Na+ derived from the exosphere. Solar wind sputtering and other processes promote neutrals from the regolith into the exosphere where they may be ionized and incorporated into the magnetospheric plasma population. At this point in time, about one year after MESSENGER's impact and one year prior to BepiColombo's launch, we review MESSENGER's observations of magnetospheric dynamics and structure. In doing so we will provide our best answers to the following six questions: Question #1: How do magnetosheath conditions at Mercury differ from what is found at the other planets? Question #2: How do conditions in Mercury's magnetosheath contribute to the dynamic nature of Mercury's magnetosphere? How does magnetopause reconnection at Mercury differ from what is seen at Earth? Are flux transfer events (FTEs) a major driver of magnetospheric convection at Mercury? Question #3: Does reconnection ever erode the dayside magnetosphere to the point where the subsolar region of the surface is exposed to direct solar wind impact? To what extent do induction currents driven in Mercury's interior limit the solar wind flux to the surface? Do FTEs contribute significantly to the solar wind flux reaching the surface? Question #4: What effects do heavy planetary ions have on Mercury's magnetosphere? Question #5: Does Mercury's magnetotail store and dissipate magnetic energy in a manner analogous to substorms at Earth? How is the process affected by the lack of an ionosphere and the expected high electrical resistivity of the crust? Question #6: How

  10. Nitrogen In Saturn's Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Smith, H. T.; Sittler, E. C.; Johnson, R. E.; McComas, D.; Reisenfeld, D.; Shappirio, M.; Michael, M.; Shematovich, V. I.; Baragiola, R. A.; Crary, F.; Young, D.

    2004-11-01

    We are analyzing CAPS instrument data on Cassini to look for nitrogen ions in Saturn's magnetosphere. Because Voyager could not separate oxygen and nitrogen, there has been considerable controversy on nitrogen's presence and relative importance. Two principal sources have been suggested: Titan's atmosphere and nitrogen species trapped in Saturn's icy satellite surfaces (Sittler et al 2004). The latter may be primordial nitrogen, likely as NH3 in ice (Stevenson 1982; Squyers et al. 1983) or nitrogen ions that have been implanted in the surface (Delitsky and Lane 2002). We will present the results of Saturnian nitrogen cloud modeling and relevant CAPS observations. We recently described the Titan source (Michael, et al. 2004; Shematovich et al. 2003; Smith et al. 2004; Sittler et al. 2004) in preparation for Cassini's Saturnian plasma measurements. Two components were identified: energetic nitrogen ions formed near Titan and energized as they diffused inward (Sittler et al. 2004) and neutrals in orbits with small perigee that became ionized in the inner magnetosphere (Smith et al 2004). The latter component would be a source of lower energy, co-rotating nitrogen ions to the inner magnetosphere. Such a component would have an energy spectrum similar to nitrogen species sputtered from the icy satellite surfaces (Johnson and Sittler 1990). However, the mass spectrum would differ, likely containing NHx and NOx species also, and, hence, may be separated from the Titan source. Our preliminary analysis for nitrogen species in the CAPS data will be compared to the models. Of interest will be the energy spectra, which can indicate whether any nitrogen present is formed locally or near Titan's orbit and diffused inward. This work is supported by the NASA Planetary Atmospheres, NASA Graduate Student Research, Virginia Space Grant Consortium Graduate Research Fellowship and the CAPS Cassini instrument team programs.

  11. Magnetospheric convection during quiet or moderately disturbed times

    NASA Technical Reports Server (NTRS)

    Caudal, G.; Blanc, M.

    1988-01-01

    The processes which contribute to the large-scale plasma circulation in the earth's environment during quiet times, or during reasonable stable magnetic conditions are reviewed. The various sources of field-aligned current generation in the solar wind and the magnetosphere are presented. The generation of field-aligned currents on open field lines connected to either polar cap and the generation of closed field lines of the inner magnetosphere are examined. Consideration is given to the hypothesis of Caudal (1987) that loss processes of trapped particles are competing with adiabatic motions in the generation of field-aligned currents in the inner magnetosphere.

  12. An Introduction to Magnetospheric Physics by Means of Simple Models

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1981-01-01

    The large scale structure and behavior of the Earth's magnetosphere is discussed. The model is suitable for inclusion in courses on space physics, plasmas, astrophysics or the Earth's environment, as well as for self-study. Nine quantitative problems, dealing with properties of linear superpositions of a dipole and a constant field are presented. Topics covered include: open and closed models of the magnetosphere; field line motion; the role of magnetic merging (reconnection); magnetospheric convection; and the origin of the magnetopause, polar cusps, and high latitude lobes.

  13. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Slavin, James A.; Krimigis, Stamatios M.; Acuña, Mario H.; Anderson, Brian J.; Baker, Daniel N.; Koehn, Patrick L.; Korth, Haje; Livi, Stefano; Mauk, Barry H.; Solomon, Sean C.; Zurbuchen, Thomas H.

    2007-08-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury offers our first opportunity to explore this planet’s miniature magnetosphere since the brief flybys of Mariner 10. Mercury’s magnetosphere is unique in many respects. The magnetosphere of Mercury is among the smallest in the solar system; its magnetic field typically stands off the solar wind only ˜1000 to 2000 km above the surface. For this reason there are no closed drift paths for energetic particles and, hence, no radiation belts. Magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere, allowing solar wind ions to impact directly the regolith. Inductive currents in Mercury’s interior may act to modify the solar wind interaction by resisting changes due to solar wind pressure variations. Indeed, observations of these induction effects may be an important source of information on the state of Mercury’s interior. In addition, Mercury’s magnetosphere is the only one with its defining magnetic flux tubes rooted beneath the solid surface as opposed to an atmosphere with a conductive ionospheric layer. This lack of an ionosphere is probably the underlying reason for the brevity of the very intense, but short-lived, ˜1-2 min, substorm-like energetic particle events observed by Mariner 10 during its first traversal of Mercury’s magnetic tail. Because of Mercury’s proximity to the sun, 0.3-0.5 AU, this magnetosphere experiences the most extreme driving forces in the solar system. All of these factors are expected to produce complicated interactions involving the exchange and recycling of neutrals and ions among the solar wind, magnetosphere, and regolith. The electrodynamics of Mercury’s magnetosphere are expected to be equally complex, with strong forcing by the solar wind, magnetic reconnection, and pick-up of planetary ions all playing roles in the generation of field-aligned electric currents. However, these field

  14. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Krimigis, Stamatios M.; Acuna, Mario H.; Anderson, Brian J.; Baker, Daniel N.; Koehn, Patrick L.; Korth, Haje; Levi, Stefano; Mauk, Barry H.; Solomon, Sean C.; Zurbuchen, Thomas H.

    2005-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet s miniature magnetosphere since the brief flybys of Mariner 10. Mercury s magnetosphere is unique in many respects. The magnetosphere of Mercury is among the smallest in the solar system; its magnetic field typically stands off the solar wind only - 1000 to 2000 km above the surface. For this reason there are no closed drift paths for energetic particles and, hence, no radiation belts. The characteristic time scales for wave propagation and convective transport are short and kinetic and fluid modes may be coupled. Magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere allowing solar wind ions to impact directly the regolith. Inductive currents in Mercury s interior may act to modify the solar wind interaction by resisting changes due to solar wind pressure variations. Indeed, observations of these induction effects may be an important source of information on the state of Mercury s interior. In addition, Mercury s magnetosphere is the only one with its defining magnetic flux tubes rooted in a planetary regolith as opposed to an atmosphere with a conductive ionospheric layer. This lack of an ionosphere is probably the underlying reason for the brevity of the very intense, but short-lived, - 1-2 min, substorm-like energetic particle events observed by Mariner 10 during its first traversal of Mercury s magnetic tail. Because of Mercury s proximity to the sun, 0.3 - 0.5 AU, this magnetosphere experiences the most extreme driving forces in the solar system. All of these factors are expected to produce complicated interactions involving the exchange and re-cycling of neutrals and ions between the solar wind, magnetosphere, and regolith. The electrodynamics of Mercury s magnetosphere are expected to be equally complex, with strong forcing by the solar wind, magnetic reconnection at the magnetopause and in the tail, and the pick-up of planetary ions all

  15. A Seasonal Study of Uranus' Magnetosphere

    NASA Astrophysics Data System (ADS)

    Cao, X.; Paty, C. S.

    2014-12-01

    The magnetospheres of the ice giant planets Uranus and Neptune are distinct from those of other major planets, including Earth, Jupiter or Saturn, because of their unique magnetic geometry: large obliquity, off-centered dipole moment, highly tilted angel between rotational axis and magnetic axis, and rapid rotation. We investigate the locations and shapes of critical boundary layers within these magnetospheres, specifically the bow shock, magnetopause and magnetotail, in order to more fully understand the complex interaction of the solar wind with these planets. To perform this study, we implement a multifluid MHD simulation capable of modeling the interplanetary solar wind interaction with the intrinsic magnetic field of the ice giant planets. These simulations are useful in that they can track individual fluids for electrons and different ion species and sources, which is important for understanding the interaction at the ice giant planets where differentiating between natively sourced ionospheric ions and externally sourced solar wind ions may be necessary due to their inherently different temperatures and compositions. Our simulations demonstrate that Uranus has an asymmetric and dynamic magnetosphere during solstice conditions, and that the asymmetry of magnetosphere might be quasi-periodic with rotation. We also investigate the magnetic structure and current systems in the magnetotail region, which can be used to understanding the global transport of plasma within the magnetosphere and hence dynamic responses to solar wind forcing and substorms. We will also present new simulations of Uranus' global magnetosphere for equinox conditions, and provide predictions for auroral locations which we will then place in the context of recent Hubble Space Telescope observations.

  16. Magnetospheric Sawtooth Oscillations Induced by Ionospheric Outflow

    NASA Astrophysics Data System (ADS)

    Brambles, O. J.; Lotko, W.; Zhang, B.; Lyon, J.; Wiltberger, M. J.

    2010-12-01

    This paper aims to address why sawtooth oscillations occur and what factors affect their periodicity. We use a multifluid version of the LFM global simulation model, driven by a steady solar wind to examine the effects of ion outflow on convection in the magnetosphere. In the simulation model, the properties of cusp and auroral region O+ outflow are causally regulated by electron precipitation and electromagnetic power flowing into the ionosphere. It is found that when ion outflow is included in the simulation, the solar wind-magnetosphere-ionosphere interaction can generate periodic substorms which appear as sawtooth-like oscillations in the geostationary magnetic field. The ion outflow enhances plasma pressure in the inner magnetosphere and the associated diamagnetic ring current stretches the field lines throughout the nightside, essentially from dawn to dusk. If the field lines are sufficiently stretched they reconnect and dipolarize, ejecting a plasmoid downtail. This cycle repeats forming multiple sawtooth oscillations. The periodicity of the sawtooth oscillation depends largely upon the strength of the outflow. The strength of outflow is varied in the simulation by changing both the driving conditions (which affects the power flowing into the ionosphere) and through direct modification of the constants in the empirical relationships. Higher outflow fluences produce oscillations with shorter periods. The period of the oscillation is found to vary in the simulations from approximately 2 hours to 6 hours depending upon the strength of the outflow. For a smaller solar wind electric field the outflow fluence is not large enough to stretch the nightside field lines enough for sawtooth oscillations to form and the magnetosphere goes into a steady magnetosphere convection (SMC) mode. As the solar wind electric field increases the outflow fluence becomes sufficiently large to affect the convection in the magnetosphere and generate sawtooth oscillations. The strength

  17. Magnetosphere of Saturn

    NASA Technical Reports Server (NTRS)

    Siscoe, G. L.

    1978-01-01

    Models of the Saturnian magnetosphere based on the application of magnetospheric scaling relations to a spin-aligned planetary magnetic dipole, that produces a surface equatorial field strength in the range 0.5 to 2 gauss, exhibit the following properties: (1) The orbit of Titan lies inside of the magnetosphere essentially all of the time, even when variations in the size of the magnetosphere resulting from solar wind pressure changes are taken into account; (2) the Brice-type planetary plasmasphere reaches a peak density of about 10 protons cm/3 at L approximately 7 (L = planetocentric distance in units of planetary radii); (3) Saturn's rings have a profound effect on the energetic particle population and the plasmaspheres derived from interstellar neutrals and Titan's torus; (4) the model calculation suggests that the Titan-derived plasmasphere may be self-amplifying with a feed-back factor greater than unity, which implies the possibility of a non-linearly saturated, highly inflated Saturnian magnetosphere; and (5) this same source can have important eroding effects on the outer edge of the rings determined by Brown-Lauzerotti sputtering rates.

  18. Geospace Magnetospheric Dynamics Mission

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Kluever, C.; Burch, J. L.; Fennell, J. F.; Hack, K.; Hillard, G. B.; Kurth, W. S.; Lopez, R. E.; Luhmann, J. G.; Martin, J. B.; Hanson, J. E.

    1998-01-01

    The Geospace Magnetospheric Dynamics (GMD) mission is designed to provide very closely spaced, multipoint measurements in the thin current sheets of the magnetosphere to determine the relation between small scale processes and the global dynamics of the magnetosphere. Its trajectory is specifically designed to optimize the time spent in the current layers and to minimize radiation damage to the spacecraft. Observations are concentrated in the region 8 to 40 R(sub E) The mission consists of three phases. After a launch into geostationary transfer orbit the orbits are circularized to probe the region between geostationary orbit and the magnetopause; next the orbit is elongated keeping perigee at the magnetopause while keeping the line of apsides down the tail. Finally, once apogee reaches 40 R(sub E) the inclination is changed so that the orbit will match the profile of the noon-midnight meridian of the magnetosphere. This mission consists of 4 solar electrically propelled vehicles, each with a single NSTAR thruster utilizing 100 kg of Xe to tour the magnetosphere in the course of a 4.4 year mission, the same thrusters that have been successfully tested on the Deep Space-1 mission.

  19. Atomic and molecular hydrogen from Titan in the Kronian magnetosphere

    NASA Technical Reports Server (NTRS)

    Eviatar, Aharon; Podolak, Morris; Richardson, John D.

    1990-01-01

    The question of the neutral gas and plasma population in the region of the Kronian magnetosphere, outside the plasma mantle and inside the magnetopause, dominated by the efflux of Titan's atmosphere is considered. A model that has been used successfully to describe the inner magnetosphere is applied to this region under constraints derived from the plasma science and ultraviolet spectrometer experiments on Voyager. It is shown that it is not possible to reconcile the results of these two experiments simultaneously with the values of the atomic and molecular source strengths of the atmosphere of Titan extant in the literature. The possible sources of the discrepancy are delineated.

  20. Pulsar magnetosphere: a new view from PIC simulations

    NASA Astrophysics Data System (ADS)

    Brambilla, Gabriele; Kalapotharakos, Constantions; Timokhin, Andrey; Harding, Alice; Kazanas, Demosthenes

    2017-01-01

    Pulsar emission is produced by charged particles that are accelerated as they flow in the star's magnetosphere. The magnetosphere is populated by electrons and positrons while the physical conditions are characterized by the so called force-free regime. However, the magnetospheric plasma configuration is still unknown, besides some general features, which inhibits the understanding of the emission generation. Here we show the closest to force-free solution ever obtained with a particle-in-cell (PIC) code. The importance of obtaining a force-free solution with PIC is that we can understand how the different particle species support the corresponding magnetosphere structure. Moreover, some aspects of the emission generation are captured. These are the necessary steps to go toward a self consistent modeling of the magnetosphere, connecting the microphysics of the pair plasma to its macroscopic quantities. Understanding the pulsar magnetosphere is essential for interpreting the broad neutron star phenomenology (young pulsars, magnetars, millisecond pulsars, etc.). The study of these plasma physics processes is also crucial for putting limits on the ability of these objects to accelerate particles.

  1. The aurora and the magnetosphere - The Chapman Memorial Lecture. [dynamo theory development, 1600-present

    NASA Technical Reports Server (NTRS)

    Akasofu, S.-I.

    1974-01-01

    Review of recent progress in magnetospheric physics, in particular, in understanding the magnetospheric substorm. It is shown that a number of magnetospheric phenomena can now be understood by viewing the solar wind-magnetosphere interaction as an MHD dynamo; auroral phenomena are powered by the dynamo. Also, magnetospheric responses to variations of the north-south and east-west components of the interplanetary magnetic field have been identified. The magnetospheric substorm is entirely different from the responses of the magnetosphere to the southward component of the interplanetary magnetic field. It may be associated with the formation of a neutral line within the plasma sheet and with an enhanced reconnection along the line. A number of substorm-associated phenomena can be understood by noting that the new neutral line formation is caused by a short-circuiting of a part of the magnetotail current.

  2. An Interpretation of Banded Magnetospheric Radio Emissions

    NASA Technical Reports Server (NTRS)

    Benson, Robert F.; Osherovich, V. A.; Fainberg, J.; Vinas, A. F.; Ruppert, D. R.; Vondrak, Richard R. (Technical Monitor)

    2000-01-01

    Recently-published Active Magnetospheric Particle Tracer Explorer/Isothermal Remanent Magnetization (AMPTE/IRM) banded magnetospheric emissions, commonly referred to as '(n + 1/2)f(sub ce)' emissions where f(sub ce) is the electron gyrofrequency, are analyzed by treating them as analogous to sounder-stimulated ionospheric emissions. We show that both individual AMPTE/IRM spectra of magnetospheric banded emissions, and a statistically-derived spectra observed over the two-year lifetime of the mission, can be interpreted in a self-consistent manner. The analysis, which predicts all spectral peaks within 4% of the observed peaks, interprets the higher-frequency emissions as due to low group-velocity Bernstein-mode waves and the lower-frequency emissions as eigen modes of cylindrical-electromagnetic-plasma-oscillations. The demarcation between these two classes of emissions is the electron plasma frequency f(sub pe), where an emission is often observed. This f(sub pe), emission is not necessarily the strongest. None of the observed banded emissions were attributed to the upper-hybrid frequency. We present Alouette-2 and ISIS-1 plasma-resonance data, and model electron temperature (T(sub e)) values, to support the argument that the frequency-spectrum of ionospheric sounder-stimulated emissions is not strongly temperature dependent and thus that the interpretation of these emissions in the ionosphere is relevant to other plasmas (such as the magnetosphere) where N(sub e) and T(sub e) can be quite different but where the ratio f(sub pe)/f(sub ce) is identical.

  3. How Ionospheric Ions Populate the Magnetosphere during a Magnetic Storm

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching; Moore, T. E.; Kistler, L. M.; Slinker, S. P.; Fedder, J. A.; Delcourt, D. C.

    2008-01-01

    Ionospheric oxygen ions have been observed throughout the magnetosphere, from the plasma sheet to the ring current region. I t has been found that the O+ /H+ density ratio in the magnetosphere increases with geomagnetic activity and varies with storm phases. During the magnetic storm in late September to earIy October 2002, Cluster was orbiting in the plasma sheet and ring current regions. At prestorm time, Cluster observed high H+ density and low O+ density in the plasma sheet and lobes. During the storm main phase, 0+ density has increased by 10 times over the pre-storm level. Strong field-aligned beams of O+ were observed in the lobes. O+ fluxes were significantly reduced in the central plasma sheet during the storm recovery. However, 0+ was still evident on the boundaries of the plasma sheet and in the lobes. In order to interpret the Cluster observations and to understand how O+ ions populate the magnetosphere during a magnetic storm, we model the storm in early October 2002 using our global ion kinetic simulation (GIK). We use the LFN global simulation model to produce electric and magnetic fields in the outer magnetosphere, the Strangeway outflow scaling with Delcourt ion trajectories to include ionospheric outflows, and the Fok inner magnetospheric model for the plasmaspheric and ring current response to all particle populations. We find that the observed composition features are qualitatively reproduced by the simulations, with some quantitative differences that point to future improvements in the models.

  4. Modelling of auroral electrodynamical processes: Magnetosphere to mesosphere. Final Report

    SciTech Connect

    Chiu, Y.T.; Gorney, D.J.

    1982-01-01

    Research conducted on auroral electrodynamic coupling between the magnetosphere and ionosphere-atmosphere in support of the development of a global scale kinetic plasma theory is reviewed. Topics covered include electric potential structure in the evening sector, morning and dayside auroras, auroral plasma formation, electrodynamic coupling with the thermosphere, and auroral electron interaction with the atmosphere.

  5. Pair-Starved Pulsar Magnetospheres

    NASA Technical Reports Server (NTRS)

    Muslimov, Alex G.; Harding, Alice K.

    2009-01-01

    We propose a simple analytic model for the innermost (within the light cylinder of canonical radius, approx. c/Omega) structure of open-magnetic-field lines of a rotating neutron star (NS) with relativistic outflow of charged particles (electrons/positrons) and arbitrary angle between the NS spin and magnetic axes. We present the self-consistent solution of Maxwell's equations for the magnetic field and electric current in the pair-starved regime where the density of electron-positron plasma generated above the pulsar polar cap is not sufficient to completely screen the accelerating electric field and thus establish thee E . B = 0 condition above the pair-formation front up to the very high altitudes within the light cylinder. The proposed mode1 may provide a theoretical framework for developing the refined model of the global pair-starved pulsar magnetosphere.

  6. Recent results in the Los Alamos compact torus program

    SciTech Connect

    Tuszewski, M.; Armstrong, W.T.; Barnes, C.W.

    1983-01-01

    A Compact Toroid is a toroidal magnetic-plasma-containment geometry in which no conductors or vacuum-chamber walls pass through the hole in the torus. Two types of compact toroids are studied experimentally and theoretically at Los Alamos: spheromaks that are oblate in shape and contain both toroidal and poloidal magnetic fields, and field-reversed configurations (FRC) that are very prolate and contain poloidal field only.

  7. Inertial Confinement Fusion Research at LOS Alamos National Laboratory

    NASA Astrophysics Data System (ADS)

    Batha, S. H.; Albright, B. J.; Alexander, D. J.; Barnes, Cris W.; Bradley, P. A.; Cobble, J. A.; Cooley, J. C.; Cooley, J. H.; Day, R. D.; DeFriend, K. A.; Delamater, N. D.; Dodd, E. S.; Fatherley, V. E.; Fernandez, J. C.; Flippo, K. A.; Grim, G. P.; Goldman, S. R.; Greenfield, S. R.; Herrmann, H. W.; Hoffman, N. M.; Holmes, R. L.; Johnson, R. P.; Keiter, P. A.; Kline, J. L.; Kyrala, G. A.; Lanier, N. E.; Loomis, E.; Lopez, F. E.; Luo, S.; Mack, J. M.; Magelssen, G. R.; Montgomery, D. S.; Nobile, A.; Oertel, J. A.; Reardon, P.; Rose, H. A.; Schmidt, D.; Schmitt, M. J.; Seifter, A.; Shimada, T.; Swift, D. C.; Tierney, T. E.; Welser-Sherrill, L.; Wilke, M. D.; Wilson, D. C.; Workman, J.; Yin, L.

    2009-07-01

    Inertial confinement fusion research at Los Alamos National Laboratory is focused on high-leverage areas of thermonuclear ignition to which LANL can apply its historic strengths and that are complementary to high-energy-density-physics topics. Using the Trident and Omega laser facilities, experiments are pursued in laser-plasma instabilities, symmetry, Be technologies, neutron and fusion-product diagnostics, and defect hydrodynamics.

  8. Magnetospheric configuration and dynamics of Saturn's magnetosphere: A global MHD simulation

    NASA Astrophysics Data System (ADS)

    Jia, Xianzhe; Hansen, Kenneth C.; Gombosi, Tamas I.; Kivelson, Margaret G.; Tóth, Gabor; DeZeeuw, Darren L.; Ridley, Aaron J.

    2012-05-01

    We investigate the solar wind interaction with Saturn's magnetosphere by using a global magnetohydrodynamic simulation driven by an idealized time-varying solar wind input that includes features of Corotating Interaction Regions typically seen at Saturn. Our model results indicate that the compressibility of Saturn's magnetosphere is intermediate between the Earth's and Jupiter's, and the magnetopause location appears insensitive to the orientation of the interplanetary magnetic field. The modeled dependences of both the magnetopause and bow shock locations on the solar wind dynamic pressure agree reasonably well with those of data-based empirical models. Our model shows that the centrifugal acceleration of mass-loaded flux tubes leads to reconnection on closed field lines forming plasmoids, an intrinsic process (“Vasyliūnas-cycle”) in Saturn's magnetosphere taking place independent of the external conditions. In addition, another type of reconnection process involving open flux tubes (“Dungey-cycle”) is also seen in our simulation when the external condition is favorable for dayside reconnection. Under such circumstances, plasmoid formation in the tail involves reconnection between open field lines in the lobes, producing stronger global impacts on the magnetosphere and ionosphere compared to that imposed by the Vasyliūnas-cycle directly. Our model also shows that large-scale tail reconnection may be induced by compressions driven by interplanetary shocks. In our simulation, large-scale tail reconnection and plasmoid formation take place in a quasi-periodic manner but the recurrence rate tends to be higher as the dynamic pressure becomes higher. While large-scale plasmoid release clearly is an important process in controlling the magnetospheric dynamics, it appears insufficient to account for all the losses of plasma added by the magnetospheric sources. We find that a large fraction of the planetary plasma is lost through the magnetotail near the flanks

  9. Satellites monitor Los Alamos fires

    NASA Astrophysics Data System (ADS)

    Kalluri, Satya; White, Benjamin

    A man-made fire that was intended to be a “controlled burn” for clearing brush and wilderness at the Bandelier National Monument, New Mexico, became an inferno that devastated significant portions of Los Alamos during the first week of May 2000. Now known as the Cerro Grande fire, it was not confined to Los Alamos alone. The fire spread to 15% of the Santa Clara Indian Reservation and a substantial area of the surrounding national parks and U.S. forests.The National Weather Service estimates that more than 100,000 fires occur in the natural environment each year within the United States alone, of which about 90% are manmade. Remote sensing images from satellites could be used to detect and monitor these active fires and biomass burning. Forest fires have a significant environmental and economic impact, and timely information about their location and magnitude is essential to contain them.

  10. Ionosphere-magnetosphere coupling

    NASA Technical Reports Server (NTRS)

    Kaufmann, Richard L.

    1994-01-01

    Principal results are presented for the four papers that were supported from this grant. These papers include: 'Mapping and Energization in the Magnetotail. 1. Magnetospheric Boundaries; 'Mapping and Energization in the Magnetotail. 2. Particle Acceleration'; 'Cross-Tail Current: Resonant Orbits'; and 'Cross-Tail Current, Field-Aligned Current, and B(sub y)'.

  11. Solar wind influence on Jupiter's magnetosphere and aurora

    NASA Astrophysics Data System (ADS)

    Vogt, Marissa; Gyalay, Szilard; Withers, Paul

    2016-04-01

    Jupiter's magnetosphere is often said to be rotationally driven, with strong centrifugal stresses due to large spatial scales and a rapid planetary rotation period. For example, the main auroral emission at Jupiter is not due to the magnetosphere-solar wind interaction but is driven by a system of corotation enforcement currents that arises to speed up outflowing Iogenic plasma. Additionally, processes like tail reconnection are also thought to be driven, at least in part, by processes internal to the magnetosphere. While the solar wind is generally expected to have only a small influence on Jupiter's magnetosphere and aurora, there is considerable observational evidence that the solar wind does affect the magnetopause standoff distance, auroral radio emissions, and the position and brightness of the UV auroral emissions. We will report on the results of a comprehensive, quantitative study of the influence of the solar wind on various magnetospheric data sets measured by the Galileo mission from 1996 to 2003. Using the Michigan Solar Wind Model (mSWiM) to predict the solar wind conditions upstream of Jupiter, we have identified intervals of high and low solar wind dynamic pressure. We can use this information to quantify how a magnetospheric compression affects the magnetospheric field configuration, which in turn will affect the ionospheric mapping of the main auroral emission. We also consider whether there is evidence that reconnection events occur preferentially during certain solar wind conditions or that the solar wind modulates the quasi-periodicity seen in the magnetic field dipolarizations and flow bursts.

  12. Multi-Scale Modeling of Magnetospheric Reconnection

    NASA Technical Reports Server (NTRS)

    Kuznetsova, M. M.; Hesse, M.; Rastatter, L.; Toth, G.; Dezeeuw, D.; Gomobosi, T.

    2007-01-01

    One of the major challenges in modeling the magnetospheric magnetic reconnection is to quantify the interaction between large-scale global magnetospheric dynamics and microphysical processes in diffusion regions near reconnection sites. There is still considerable debate as to what degree microphysical processes on kinetic scales affect the global evolution and how important it is to substitute numerical dissipation and/or ad hoc anomalous resistivity by a physically motivated model of dissipation. Comparative studies of magnetic reconnection in small scale geometries demonstrated that MHD simulations that included non-ideal processes in terms of a resistive term $\\eta J$ did not produce the fast reconnection rates observed in kinetic simulations. For a broad range of physical parameters in collisionless magnetospheric plasma, the primary mechanism controlling the dissipation in the vicinity of the reconnection site is non-gyrotropic effects with spatial scales comparable with the particle Larmor radius. We utilize the global MHD code BATSRUS and incorporate nongyrotropic effects in diffusion regions in terms of corrections to the induction equation. We developed an algorithm to search for magnetotail reconnection sites, specifically where the magnetic field components perpendicular to the local current direction approaches zero and form an X-type configuration. Spatial scales of the diffusion region and magnitude of the reconnection electric field are calculated selfconsistently using MHD plasma and field parameters in the vicinity of the reconnection site. The location of the reconnection sites is updated during the simulations. To clarify the role of nongyrotropic effects in diffusion region on the global magnetospheric dynamic we perform simulations with steady southward IMF driving of the magnetosphere. Ideal MHD simulations with magnetic reconnection supported by numerical resistivity produce steady configuration with almost stationary near-earth neutral

  13. Magnetic field characters of returning flux tubes in Saturn's magnetosphere

    NASA Astrophysics Data System (ADS)

    Lai, Hairong; Russell, Christopher; Jia, Yingdong; Wei, Hanying

    2016-04-01

    Deep in the Saturnian magnetosphere, water-group neutrals are ionized after being released from the plume of Enceladus at 4 RS. This forms a plasma disk from 2.5 to 8 RS around Saturn and the typical source rate is 12~250 kg/s. Such plasma addition must be shed to the solar wind ultimately to maintain the plasma density in the magnetosphere in long term average. In this plasma transfer process, the magnetic flux also convects outward. To conserve the total magnetic flux imposed on the magnetosphere by the planet's internal dynamo, the magnetic flux has to return to the inner magnetosphere. Flux tubes are found to be the major form of such return. Determining such flux tubes is essential in understanding the breathing of Saturn magnetosphere. We investigated 10 years of Cassini magnetometer data to identify over six hundred flux-returning events between 4 and 18 in L. Statistical properties are presented, to constrain the origin, transport and evolution of these flux tubes.

  14. Low energy neutral atoms in the earth's magnetosphere: Modeling

    SciTech Connect

    Moore, K.R.; McComas, D.J.; Funsten, H.O.; Thomsen, M.F.

    1992-01-01

    Detection of low energy neutral atoms (LENAs) produced by the interaction of the Earth's geocorona with ambient space plasma has been proposed as a technique to obtain global information about the magnetosphere. Recent instrumentation advances reported previously and in these proceedings provide an opportunity for detecting LENAs in the energy range of <1 keV to {approximately}50 keV. In this paper, we present results from a numerical model which calculates line of sight LENA fluxes expected at a remote orbiting spacecraft for various magnetospheric plasma regimes. This model uses measured charge exchange cross sections, either of two neural hydrogen geocorona models, and various empirical modes of the ring current and plasma sheet to calculate the contribution to the integrated directional flux from each point along the line of sight of the instrument. We discuss implications for LENA imaging of the magnetosphere based on these simulations. 22 refs.

  15. The Relation Between Magnetospheric State Parameters and the Occurrence of Plasma Depletion Events in the Night-Time Mid-Latitude F-Region

    NASA Technical Reports Server (NTRS)

    Seker, Ilgin; Fung, Shing F.; Mathews, John D.

    2010-01-01

    Studies using all-sky imagers have revealed the presence of various ionospheric irregularities in the night-time mid-latitude F-region. The most prevalent and well known of these are the Medium Scale Traveling Ionospheric Disturbances (MSTIDs) that usually occur when the geomagnetic activity is low, and mid-latitude spread-F plumes that are often observed when the geomagnetic activity is high. The inverse and direct relations between geomagnetic activity (particularly Kp) and the occurrence rate of MSTIDs and midlatitude plumes, respectively, have been observed by several studies using different instruments. In order to understand the underlying causes of these two relations, it is illuminating to better characterize the occurrence of MSTIDs and plumes using multiple magnetospheric state parameters. Here we statistically compare multiple geomagnetic driver and response parameters (such as Kp, AE, Dst, and solar wind parameters) with the occurrence rates of night-time MSTIDs and plumes observed using an all-sky imager at Arecibo Observatory (AO) between 2003 and 2008. The results not only allow us to better distinguish MSTIDs and plumes, but also shed further light on the generation mechanism and electrodynamics of these two different phenomena occurring at night-time in the mid-latitude F-region.

  16. Europa's Interaction with the Magnetosphere of Jupiter

    NASA Astrophysics Data System (ADS)

    Khurana, Krishan K.; Jia, Xianzhe; Paranicas, Chris; Cassidy, Timothy A.; Hansen, Kenneth C.

    2013-04-01

    Galileo's observations of magnetic field in the vicinity of Europa have shown that Europa does not possess an appreciable internal magnetic field. However, Europa strongly modifies its plasma and magnetic field environment by directly interacting with the magnetosphere of Jupiter. The plasma interactions cause the absorption of Jovian plasma by the moon, pick-up of newly formed ions from the exospheres of the moon, plasma diversion by electrodynamic (Alfvén wing) interaction and the formation of a long wake in the downstream region. In addition to the electrodynamic interactions, Europa also displays electromagnetic induction response to the rotating field of Jupiter presumably from the conducting presence of global salty liquid oceans inside the moon. Galileo successfully encountered Europa 10 times during its mission. We are developing quantitative 3-D MHD models of plasma interactions of Europa with Jupiter's magnetosphere. In these models we include the effects of plasma pick-up and plasma interaction with a realistic exosphere as well as the contribution of the electromagnetic induction. We will present results of these quantitative models and show that the plasma interaction is strongest when Europa is located at the center of Jupiter's current sheet. We find that plasma mass loading rates are extremely variable over time. We will investigate various mechanisms by which such variability in mass-loading could be produced including episodically enhanced sputtering from trapped gaseous molecules in ice and enhanced plasma interaction with a vent(s) generated dense exosphere. The new model will aid researchers in planning observations from future missions such as JUICE and Europa flagship mission.

  17. Upstream Structures and Their Effects on the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.

    2011-01-01

    Kinetic processes within the Earth's foreshock generate a profusion of plasma and magnetic field structures with sizes and durations ranging from the microscale (e.g. SLAMs, solitons, and density holes) to the mesoscale (e.g. foreshock cavities or boundaries, hot flow anomalies, and bubbles). Swept into the bow shock by the solar wind flow, the perturbations associated with these features batter the magnetosphere, driving a wide variety of magnetospheric effects, including large amplitude magnetopause motion, bursty reconnection and the generation of flux transfer events, enhanced pulsation activity within the magnetosphere, diffusion and energization of radiation belt particles, enhanced particle precipitation resulting in dayside aurora and riometer absorption, and the generation of field-aligned currents and magnetic impulse events in high-latitude ground magnetometers. This talk reviews the ever growing menagery of structures observed upstream from the bow shock, examines their possible interrelationships, and considers their magnetospheric consequences.

  18. Effect of outer magnetosphere pre-conditioning on the inner magnetosphere during a magnetic storm

    NASA Astrophysics Data System (ADS)

    Li, W.; Raeder, J.; Ge, Y.; Gilson, M. L.

    2013-12-01

    It has been suggested that the plasma sheet conditions prior to the main phase of a geomagnetic storm can have a significant effect on the storm development and the minimum Dst. In particular, northward IMF conditions leading up to the storm may load the plasma sheet with cold dense plasma and lead to stronger storms as opposed to those storms that lack a northward IMF phase before storm commencement. We use the OpenGGCM-RCM model to simulate storm events with northward IMF preconditioning before the storm commences. We will show in the simulation how a cold dense plasma sheet is formed in the mid-tail plasma sheet, how a super-dense plasma sheet develops near the inner magnetosphere boundary, and how this dense plasma affects the ring current and Dst index in the storm main phase. In order to quantify the effect we will present comparisons of simulations of the same storm with and without preconditioning by northward IMF.

  19. Decrease of keV electron and ion fluxes in the dayside magnetosphere during the early phase of magnetospheric disturbances

    NASA Technical Reports Server (NTRS)

    Hultqvist, B.; Aparicio, B.; Borg, H.; Arnoldy, R.; Moore, T. E.

    1981-01-01

    It is shown that a decrease of the keV particle fluxes in the dayside magnetosphere near the geosynchronous orbit is characteristic of the first several hours of magnetospheric disturbances. After some hours newly injected plasma from the nightside reaches the 'evacuated' regions of the dayside magnetosphere and strong flux increases are observed. The 'evacuation' of the dayside magnetosphere is interpreted in terms of a change in the convection pattern associated with an increase of the large scale electric field at the onset of the disturbance. The model presented is capable of accommodating all characteristics of the observational data, such as the temporal and spatial distributions, energy and pitch angle characteristics, and differences between electrons and protons.

  20. Survey of electrons in the Uranian magnetosphere - Voyager 2 observations

    NASA Technical Reports Server (NTRS)

    Sittler, Edward C., Jr.; Ogilvie, Keith W.; Selesnick, Richard

    1987-01-01

    Results of an analysis of the Voyager 2 plasma-science-experiment electron measurements made during the Uranus encounter are presented. The energy coverage is in the range of 10 to 5950 eV. The large day-night asymmetry together with the spin axis alignment with the solar direction and the large tilt of the planetary magnetic dipole suggest that solar-wind-driven time-dependent magnetospheric convection will be an important transport mechanism within the Uranian magnetosphere. The steady state convection time of the plasma is estimated to be between 1 and 3 days.

  1. AXISYMMETRIC, NONSTATIONARY BLACK HOLE MAGNETOSPHERES: REVISITED

    SciTech Connect

    Song, Yoo Geun; Park, Seok Jae E-mail: sjpark@kasi.re.kr

    2015-10-10

    An axisymmetric, stationary, general-relativistic, electrodynamic engine model of an active galactic nucleus was formulated by Macdonald and Thorne that consisted of a supermassive black hole surrounded by a plasma magnetosphere and a magnetized accretion disk. Based on this initial formulation, a nonstationary, force-free version of their model was constructed by Park and Vishniac (PV), with the simplifying assumption that the poloidal component of the magnetic field line velocity be confined along the radial direction in cylindrical polar coordinates. In this paper, we derive the new, nonstationary “Transfield Equation,” which was not specified in PV. If we can solve this “Transfield Equation” numerically, then we will understand the axisymmetric, nonstationary black hole magnetosphere in more rigorous ways.

  2. Global ENA Imaging of Earth's Dynamic Magnetosphere

    NASA Astrophysics Data System (ADS)

    Brandt, Pontus

    2015-04-01

    The interaction between singly charged ions of Earth's magnetosphere and its neutral exosphere and upper atmosphere gives rise to Energetic Neutral Atoms (ENAs). This has enabled several missions to remotely image the global injection dynamics of the ring current and plasma sheet, the outflow of ions from Earth's polar regions, and the location of the sub-solar magnetopause. In this presentation we review ENA observations by the Astrid, IMAGE, TWINS and IBEX missions. We focus on results from the IMAGE/HENA Camera including observations of proton and oxygen ion injections in to the ring current and their impact on the force-balance and ionospheric coupling in the inner magnetosphere. We report also on the status of inversion techniques for retrieving the ion spatial and pitch-angle distributions from ENA images. The presentation concludes with a discussion of future next steps in ENA instrumentation and analysis capabilities required to deliver the science as recommended by the Heliophysics Decadal Survey.

  3. Cosmogony as an extrapolation of magnetospheric research

    NASA Technical Reports Server (NTRS)

    Alfven, H.

    1984-01-01

    A theory of the origin and evolution of the Solar System which considered electromagnetic forces and plasma effects is revised in light of information supplied by space research. In situ measurements in the magnetospheres and solar wind can be extrapolated outwards in space, to interstellar clouds, and backwards in time, to the formation of the solar system. The first extrapolation leads to a revision of cloud properties essential for the early phases in the formation of stars and solar nebulae. The latter extrapolation facilitates analysis of the cosmogonic processes by extrapolation of magnetospheric phenomena. Pioneer-Voyager observations of the Saturnian rings indicate that essential parts of their structure are fossils from cosmogonic times. By using detailed information from these space missions, it is possible to reconstruct events 4 to 5 billion years ago with an accuracy of a few percent.

  4. Mercury's magnetosphere after MESSENGER's first flyby.

    PubMed

    Slavin, James A; Acuña, Mario H; Anderson, Brian J; Baker, Daniel N; Benna, Mehdi; Gloeckler, George; Gold, Robert E; Ho, George C; Killen, Rosemary M; Korth, Haje; Krimigis, Stamatios M; McNutt, Ralph L; Nittler, Larry R; Raines, Jim M; Schriver, David; Solomon, Sean C; Starr, Richard D; Trávnícek, Pavel; Zurbuchen, Thomas H

    2008-07-04

    Observations by MESSENGER show that Mercury's magnetosphere is immersed in a comet-like cloud of planetary ions. The most abundant, Na+, is broadly distributed but exhibits flux maxima in the magnetosheath, where the local plasma flow speed is high, and near the spacecraft's closest approach, where atmospheric density should peak. The magnetic field showed reconnection signatures in the form of flux transfer events, azimuthal rotations consistent with Kelvin-Helmholtz waves along the magnetopause, and extensive ultralow-frequency wave activity. Two outbound current sheet boundaries were observed, across which the magnetic field decreased in a manner suggestive of a double magnetopause. The separation of these current layers, comparable to the gyro-radius of a Na+ pickup ion entering the magnetosphere after being accelerated in the magnetosheath, may indicate a planetary ion boundary layer.

  5. Observing the magnetosphere through auroral imaging.

    NASA Astrophysics Data System (ADS)

    Mende, S. B.

    2015-12-01

    Although the terrestrial aurora is often regarded as 2 dimensional projection of the 3 dimensional magnetosphere there are fundamental limitations in observing magnetospheric processes through their auroral footprints. It has been shown that most electron auroras are produced in the auroral acceleration region at lower altitudes (<2Re) in the last steps of processing the auroral particles. From FAST, IMAGE , Cluster and THEMIS data we can distinguish between four fundamentally different types of auroral acceleration regions. A primary task is to distinguish (1) the upward current, (2) downward current, (3) diffuse aurora and (4) Alfven wave accelerated types of auroral acceleration regions. Type (1) contains the "inverted V" type electron precipitation distinguishable by several keV mono-energetic electron spectra, and low number flux consistent with the source population in the plasma sheet. Our understanding of how these auroras relate to magnetospheric processes is still vague, probably associated with convection sheer. Alfven wave electron auroras (4) are of low average energy (<2 keV) high electron flux consistent with ionospheric electron source predominantly occurring during substorms, and they are generated by wave energy carried from the magnetosphere into the ionosphere, where it is converted into electron energy. These are most promising candidates for observing the footprints of source regions associated with reconnection sites or magnetospheric dB/dt events. Optical measuring techniques of electron energy use the atmosphere as a spectrometer, obtaining the penetration altitude as a proxy for energy, that can be obtained from atmospheric composition, quenching lifetime of the emitters, UV absorption pass-length of O2 to the source or the local atmospheric temperature. Precipitating protons are usually an order of magnitude more energetic and less affected by fields in the low altitude auroral acceleration region. Energetic proton precipitation is a more

  6. Modeling of the propagation of low-frequency electromagnetic radiation in the Earth’s magnetosphere

    SciTech Connect

    Lebedev, N. V. Rudenko, V. V.

    2015-06-15

    A numerical algorithm for solving the set of differential equations describing the propagation of low-frequency electromagnetic radiation in the magnetospheric plasma, including in the presence of geomagnetic waveguides in the form of large-scale plasma density inhomogeneities stretched along the Earth’s magnetic field, has been developed. Calculations of three-dimensional ray trajectories in the magnetosphere and geomagnetic waveguide with allowance for radiation polarization have revealed characteristic tendencies in the behavior of electromagnetic parameters along the ray trajectory. The results of calculations can be used for magnetospheric plasma diagnostics.

  7. Investigations of magnetosphere-ionosphere coupling relevant to operational systems. Final scientific report, 1984-1987

    SciTech Connect

    Meng, C.I.; Newell, P.T.

    1988-02-01

    Important advances were made in understanding the dynamics of the magnetosphere and its coupling to the ionosphere. Significant progress was made in the areas of polar cusp precipitation and dynamics; dayside auroral morphology and auroral boundary dynamics; polar rain; the quiescent polar cap; the physics of impulsive injection phenomena; and problems of global magnetospheric plasma transport.

  8. The response of Jupiter's magnetosphere to an outburst on Io.

    PubMed

    Brown, M E; Bouchez, A H

    1997-10-10

    A 6-month-long monitoring campaign of the Io plasma torus and neutral cloud was conducted to determine the characteristics of their interaction. During the observations, a large outburst of material from Io-inferred to be caused by the eruption of a volcanic plume on Io-caused a transient increase in the neutral cloud and plasma torus masses. The response of the plasma torus to this outburst shows that the interaction between Io and Jupiter's magnetosphere is stabilized by a feedback mechanism in which increases in the plasma torus mass cause a nonlinear increase in loss from the plasma torus, limiting plasma buildup.

  9. Dynamics of Mars' magnetosphere

    SciTech Connect

    Kennel, C.F.; Coroniti, F.V. ); Zelenyi, L.M. ); Moses, S.L.

    1989-08-01

    If Mars has a small intrinsic magnetic moment, Mars' magnetosphere could vary on time scales of a few minutes due to reconnection with the solar wind magnetic field. The day-side magnetopause will be one or two reflected-ion Larmor radii from the bow shock. Substorms will have scale-times of about six minutes. Mars' high ionospheric conductance will virtually stop polar cap convection, and create a magnetic topological crisis unless convecting magnetic flux finds a dissipative way to return to the day-side. The strong magnetic hear induced by magnetospheric convection above the ionosphere could be tearing unstable. The magnetic field might diffusively percolate through the tearing layer. This shearing also draws field aligned currents from the ionosphere which could inject few KeV heavy ionospheric ions into the magnetotail.

  10. Currents in Saturn's magnetosphere

    NASA Technical Reports Server (NTRS)

    Connerney, J. E. P.; Acuna, M. H.; Ness, N. F.

    1983-01-01

    A model of Saturn's magnetospheric magnetic field is obtained from the Voyager 1 and 2 observations. A representation consisting of the Z sub 3 zonal harmonic model of Saturn's planetary magnetic field together with an explicit model of Saturn's planetary magnetic field and a model of the equatorial ring current fits the observations well within r 20 R sub S, with the exception of data obtained during the Voyager 2 inbound pass.

  11. Magnetospheric Multiscale Overview and Science Objectives

    NASA Astrophysics Data System (ADS)

    Burch, J. L.; Moore, T. E.; Torbert, R. B.; Giles, B. L.

    2016-03-01

    Magnetospheric Multiscale (MMS), a NASA four-spacecraft constellation mission launched on March 12, 2015, will investigate magnetic reconnection in the boundary regions of the Earth's magnetosphere, particularly along its dayside boundary with the solar wind and the neutral sheet in the magnetic tail. The most important goal of MMS is to conduct a definitive experiment to determine what causes magnetic field lines to reconnect in a collisionless plasma. The significance of the MMS results will extend far beyond the Earth's magnetosphere because reconnection is known to occur in interplanetary space and in the solar corona where it is responsible for solar flares and the disconnection events known as coronal mass ejections. Active research is also being conducted on reconnection in the laboratory and specifically in magnetic-confinement fusion devices in which it is a limiting factor in achieving and maintaining electron temperatures high enough to initiate fusion. Finally, reconnection is proposed as the cause of numerous phenomena throughout the universe such as comet-tail disconnection events, magnetar flares, supernova ejections, and dynamics of neutron-star accretion disks. The MMS mission design is focused on answering specific questions about reconnection at the Earth's magnetosphere. The prime focus of the mission is on determining the kinetic processes occurring in the electron diffusion region that are responsible for reconnection and that determine how it is initiated; but the mission will also place that physics into the context of the broad spectrum of physical processes associated with reconnection. Connections to other disciplines such as solar physics, astrophysics, and laboratory plasma physics are expected to be made through theory and modeling as informed by the MMS results.

  12. Decametric modulation lanes as a probe for inner jovian magnetosphere

    NASA Astrophysics Data System (ADS)

    Arkhypov, Oleksiy V.; Rucker, Helmut O.

    2013-11-01

    We use the specific scintillations of jovian decametric radio sources (modulation lanes), which are produced by plasma inhomogeneities in the vicinity of that planet, to probe the inner magnetosphere of Jupiter. The positions and frequency drift of 1762 lanes have been measured on the DAM spectra from archives. A special 3D algorithm is used for space localization of field-aligned magnetospheric inhomogeneities by the frequency drift of modulation lanes. As a result, the main regions of the lane formation are found: the Io plasma torus; the magnetic shell of the Gossamer Ring at Thebe and Amalthea orbits; and the region above the magnetic anomaly in the northern magnetosphere. It is shown that modulation lanes reveal the depleted magnetic tubes in practically unvisited, innermost regions of the jovian magnetosphere. The local and probably temporal plasma enhancement is found at the magnetic shell of Thebe satellite. Hence, the modulation lanes are a valuable instrument for remote sensing of those parts of jovian magnetosphere, which are not studied yet in situ.

  13. A NEW GENERATION OF LOS ALAMOS OPACITY TABLES

    SciTech Connect

    Colgan, J.; Kilcrease, D. P.; Magee, N. H.; Sherrill, M. E.; Abdallah, J. Jr.; Hakel, P.; Fontes, C. J.; Guzik, J. A.; Mussack, K. A.

    2016-02-01

    We present a new, publicly available set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our tables are computed using the Los Alamos ATOMIC opacity and plasma modeling code, and make use of atomic structure calculations that use fine-structure detail for all the elements considered. Our equation of state model, known as ChemEOS, is based on the minimization of free energy in a chemical picture and appears to be a reasonable and robust approach to determining atomic state populations over a wide range of temperatures and densities. In this paper we discuss in detail the calculations that we have performed for the 30 elements considered, and present some comparisons of our monochromatic opacities with measurements and other opacity codes. We also use our new opacity tables in solar modeling calculations and compare and contrast such modeling with previous work.

  14. A New Generation of Los Alamos Opacity Tables

    SciTech Connect

    Colgan, James Patrick; Kilcrease, David Parker; Magee, Jr., Norman H.; Sherrill, Manolo Edgar; Abdallah, Joseph; Hakel, Peter; Fontes, Christopher John; Guzik, Joyce Ann; Mussack Tamashiro, Kathleen Anita

    2016-01-26

    We present a new, publicly available, set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our tables are computed using the Los Alamos ATOMIC opacity and plasma modeling code, and make use of atomic structure calculations that use fine-structure detail for all the elements considered. Our equation-of-state (EOS) model, known as ChemEOS, is based on the minimization of free energy in a chemical picture and appears to be a reasonable and robust approach to determining atomic state populations over a wide range of temperatures and densities. In this paper we discuss in detail the calculations that we have performed for the 30 elements considered, and present some comparisons of our monochromatic opacities with measurements and other opacity codes. We also use our new opacity tables in solar modeling calculations and compare and contrast such modeling with previous work.

  15. A New Generation of Los Alamos Opacity Tables

    DOE PAGES

    Colgan, James Patrick; Kilcrease, David Parker; Magee, Jr., Norman H.; ...

    2016-01-26

    We present a new, publicly available, set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our tables are computed using the Los Alamos ATOMIC opacity and plasma modeling code, and make use of atomic structure calculations that use fine-structure detail for all the elements considered. Our equation-of-state (EOS) model, known as ChemEOS, is based on the minimization of free energy in a chemical picture and appears to be a reasonable and robust approach to determining atomic state populations over a wide range of temperatures and densities. In this paper we discuss in detail the calculations thatmore » we have performed for the 30 elements considered, and present some comparisons of our monochromatic opacities with measurements and other opacity codes. We also use our new opacity tables in solar modeling calculations and compare and contrast such modeling with previous work.« less

  16. Los Alamos Science: Number 16

    SciTech Connect

    Cooper, N.G.

    1988-01-01

    It was an unusually stimulating day and a half at Los Alamos when two Nobel Laureates in physiology, a leading paleontologist, and a leading bio-astrophysicist came together to discuss ''Unsolved Problems in the Science of Life,'' the topic of the second in a series of special meetings sponsored by the Fellows of the Laboratory. Just like the first one on ''Creativity in Science,'' this colloquium took us into a broader arena of ideas and viewpoints than is our usual daily fare. To contemplate the evolution and mysteries of intelligent life from the speakers' diverse points of view at one time, in one place was indeed a rare experience.

  17. Mercury's magnetosphere: another look

    NASA Astrophysics Data System (ADS)

    Engle, Irene M.

    1997-01-01

    The measurements made of Mercury's magnetic field during the Mercury I flyby and the Mereury III flyby have been incorporated into models of the Hermean magnetosphere-magnetotail system. When the magnetic field data for the first half of the Mereury I flyby and all of the Mercury III flyby were incorporated into a single fit of a scaled version of the Beard ( J. Geophys. Res.84, 2118-2122, 1979) Earth magnetosphere-magnetotail system, a r.m.s. deviation of 9.3 nT for the magnetic field vector was obtained (Bergan and Engle, J. Geophys. Res.86, 1617-1620, 1981). This paper presents results of a study that employs an adaptation of that Beard model but also adopts the assumption that the incident solar wind pressure was different at the times of the two Mercury magnetosphere encounters. Resulting different stand-off distances and scaling factors for the data of the two respective flybys result directly from that single assumption. The study yields a comparable fit of reduced r.m.s. deviation of 7.1 nT and a strength of the Mercury planetary dipole moment D (before any displacement effects are incorporated) between 154 nT RM3 (Merc 1) and 182 nT RM3 (Merc 3). The corresponding standoff distances are 1.31 RM for the Merc 3 encounter and 1.08 RM for the Merc 1 encounter.

  18. REVIEWS OF TOPICAL PROBLEMS: Magnetospheres of planets with an intrinsic magnetic field

    NASA Astrophysics Data System (ADS)

    Belenkaya, Elena S.

    2009-08-01

    This review presents modern views on the physics of magnetospheres of Solar System planets having an intrinsic magnetic field, and on the structure of magnetospheric magnetic fields. Magnetic fields are generated in the interiors of Mercury, Earth, Jupiter, Saturn, Uranus, and Neptune via the dynamo mechanism. These fields are so strong that they serve as obstacles for the plasma stream of the solar wind. A magnetosphere surrounding a planet forms as the result of interaction between the solar wind and the planetary magnetic field. The dynamics of magnetospheres are primary enforced by solar wind variations. Each magnetosphere is unique. The review considers common and individual sources of magnetic fields and the properties of planetary magnetospheres.

  19. RCM simulation of interchange transport in Saturn's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Liu, X.; Sazykin, S. Y.; Wolf, R.

    2013-12-01

    Numerical simulations with the Rice Convection Model have been used to study the radial transport of plasma in Saturn's inner magnetosphere (L < 12) where the magnetic field is dominated by the planetary dipole. This transport occurs through a time-variable pattern of wider outflow channels containing cool, dense plasma from interior sources, alternating with narrower inflow channels containing hot, tenuous plasma from the outer magnetosphere. The 'smoking gun' of this interchange transport process is the pervasive presence of V-shaped injection/dispersion signatures in linear energy-time spectrograms that are observed by the Cassini Plasma Spectrometer (CAPS) on every pass through the inner magnetosphere. Using observed hot plasma distributions at L~12 as input, we have now successfully simulated these V-shaped signatures. We will show these simulation results and compare them with observed signatures. We will also describe future improvements to the model including relaxing the dipole-field assumption, thus enabling us to simulate local-time asymmetries imposed by the outer magnetosphere and tail.

  20. The Parameterization of Top-Hat Particle Sensors with Microchannel-Plate-Based Detection Systems and its Application to the Fast Plasma Investigation on NASA's Magnetospheric MultiScale Mission

    NASA Technical Reports Server (NTRS)

    Gershman, Daniel J.; Gliese, Ulrik; Dorelli, John C.; Avanov, Levon A.; Barrie, Alexander C.; Chornay, Dennis J.; MacDonald, Elizabeth A.; Holland, Matthew P.; Pollock, Craig J.

    2015-01-01

    The most common instrument for low energy plasmas consists of a top-hat electrostatic analyzer geometry coupled with a microchannel-plate (MCP)-based detection system. While the electrostatic optics for such sensors are readily simulated and parameterized during the laboratory calibration process, the detection system is often less well characterized. Furthermore, due to finite resources, for large sensor suites such as the Fast Plasma Investigation (FPI) on NASA's Magnetospheric Multiscale (MMS) mission, calibration data are increasingly sparse. Measurements must be interpolated and extrapolated to understand instrument behavior for untestable operating modes and yet sensor inter-calibration is critical to mission success. To characterize instruments from a minimal set of parameters we have developed the first comprehensive mathematical description of both sensor electrostatic optics and particle detection systems. We include effects of MCP efficiency, gain, scattering, capacitive crosstalk, and charge cloud spreading at the detector output. Our parameterization enables the interpolation and extrapolation of instrument response to all relevant particle energies, detector high voltage settings, and polar angles from a small set of calibration data. We apply this model to the 32 sensor heads in the Dual Electron Sensor (DES) and 32 sensor heads in the Dual Ion Sensor (DIS) instruments on the 4 MMS observatories and use least squares fitting of calibration data to extract all key instrument parameters. Parameters that will evolve in flight, namely MCP gain, will be determined daily through application of this model to specifically tailored in-flight calibration activities, providing a robust characterization of sensor suite performance throughout mission lifetime. Beyond FPI, our model provides a valuable framework for the simulation and evaluation of future detection system designs and can be used to maximize instrument understanding with minimal calibration

  1. Plasma processes in space

    NASA Technical Reports Server (NTRS)

    Wu, C. S.

    1976-01-01

    Elementary microscopic interactions in plasmas are described. The importance of plasma physics in space studies is illustrated by examining several phenomena which cannot be explained satisfactorily by MHD theory. These include kinetic instabilities, plasma turbulence in the bow shock, magnetic turbulence near the moon, VLF emissions in the magnetosphere, planetary and solar radio emissions, and interaction of planetary and cometary plasmas with the solar wind. Evidence for the existence of anomalous transport processes in terrestrial and planetary magnetospheres is presented.

  2. A three-ring circuit model of the magnetosphere

    NASA Technical Reports Server (NTRS)

    Whipple, E. C., Jr.; Mcilwain, C. E.; Alfven, H.

    1981-01-01

    The magnetosphere is modeled by superimposing a dipole field, a uniform field and a perturbation field due to a simple current system. This current system comprises a ring current in the neutral line of the dipole plus uniform fields, together with vertical currents representing field-aligned currents to the neutral line. The current circuit is closed through two additional ring currents above and below the equatorial plane representing distributed adiabatic perpendicular currents. This system produces many magnetospheric features, among them a magnetopause, bending of magnetic field lines in the anti-solar direction, a magnetotail, and cusps in the day-side of the earth. The objective is to demonstrate that it is not necessary to think of the magnetic field topology as being caused by the flowing plasma carrying field lines. The primary physical problem is to derive the current system from the self-consistent interaction of the solar-wind and magnetospheric plasmas and fields.

  3. Representation of the Geosynchronous Plasma Environment in Spacecraft Charging Calculations

    NASA Technical Reports Server (NTRS)

    Davis, V. A.; Mandell, M. J.; Thomsen, M. F.

    2006-01-01

    Historically, our ability to predict and postdict spacecraft surface charging has been limited by the characterization of the plasma environment. One difficulty lies in the common practice of fitting the plasma data to a Maxwellian or Double Maxwellian distribution function, which may not represent the data well for charging purposes. We use electron and ion flux spectra measured by the Los Alamos National Laboratory (LANL) Magnetospheric Plasma Analyzer (MPA) to examine how the use of different spectral representations of the charged particle environment in computations of spacecraft potentials during magnetospheric substorms affects the accuracy of the results. We calculate the spacecraft potential using both the measured fluxes and several different fits to these fluxes. These measured fluxes have been corrected for the difference between the measured and calculated potential. The potential computed using the measured fluxes and the best available material properties of graphite carbon, with a secondary electron escape fraction of 81%, is within a factor of three of the measured potential for 87% of the data. Potentials calculated using a Kappa function fit to the incident electron flux distribution function and a Maxwellian function fit to the incident ion flux distribution function agree with measured potentials nearly as well as do potentials calculated using the measured fluxes. Alternative spectral representations gave less accurate estimates of potential. The use of all the components of the net flux, along with spacecraft specific average material properties, gives a better estimate of the spacecraft potential than the high energy flux alone.

  4. Alfven Waves in the Solar Wind, Magnetosheath, and Outer Magnetosphere

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.

    2007-01-01

    Alfven waves Propagating outward from the Sun are ubiquitous in the solar wind and play a major role in the solar wind-magnetosphere interaction. The passage of the waves generally occurs in the form of a series of discrete steepened discontinuities, each of which results in an abrupt change in the interplanetary magnetic field direction. Some orientations of the magnetic field permit particles energized at the Earth's bow shock to gain access to the foreshock region immediately upstream from the Earth's bow shock. The thermal pressure associated with these particles can greatly perturb solar wind plasma and magnetic field parameters shortly prior to their interaction with the Earth's bow shock and magnetosphere. The corresponding dynamic pressure variations batter the magnetosphere, driving magnetopause motion and transient compressions of the magnetospheric magnetic field. Alfven waves transmit information concerning the dynamic pressure variations applied to the magnetosphere to the ionosphere, where they generate the traveling convection vortices (TCVs) seen in high-latitude ground magnetograms. Finally, the sense of Alfvenic perturbations transmitted into the magnetosheath reverses across local noon because magnetosheath magnetic field lines drape against the magnetopause. The corresponding change in velocity perturbations must apply a weak torque to the Earth's magnetosphere.

  5. Time Evolution of Pulsar Magnetosphere: An Implicit Approach

    NASA Astrophysics Data System (ADS)

    Sreekumar, Sushilkumar; Schlegel, Eric M.

    2017-01-01

    In this project we attempt to understand the structure of pulsar magnetosphere, its dynamics and evolution. This is done by developing a computationally intense implicit finite difference (FD) approach, under the approximation of force-free electrodynamics. Recent studies have suggested an important role of current sheets (CS) in pulsar spin down mechanisms. However, its contribution to high energy emissions, flux outflow, acceleration sites and mechanisms are not completely understood. A better resolution of CS will play a significant role in our understanding of local and global structure of the magnetosphere, which is the main objective of this work. In this first of a series of studies, we demonstrate and verify the existence of CS thereby supporting the Contopoulos et al. (CKF, 1999) type magnetosphere. This is important as CKF type magnetosphere is the new benchmark in pulsar modelling. The implementation of resistivity approach and its superiority over the traditional explicit approach will be addressed. The implicit formulation in the high conductivity limit will improve our understanding of the magnetosphere where copious amount of plasma is generated. Once a consistent global structure of the magnetosphere is addressed we will identify the local models and sites to understand the acceleration mechanisms responsible for high energy emission which dominates pulsar emission.

  6. Does Solar Wind also Drive Convection in Jupiter's Magnetosphere?

    NASA Astrophysics Data System (ADS)

    Khurana, K. K.

    2001-05-01

    Using a simple model of magnetic field and plasma velocity, Brice and Ioannidis [1970] showed that the corotation electric field exceeds convection electric field throughout the Jovian magnetosphere. Since that time it has been tacitly assumed that Jupiter's magnetosphere is driven from within. If Brice and Ioannidis conjecture is correct then one would not expect major asymmetries in the field and plasma parameters in the middle magnetosphere of Jupiter. Yet, new field and plasma observations from Galileo and simultaneous auroral observations from HST show that there are large dawn/dusk and day/night asymmetries in many magnetospheric parameters. For example, the magnetic observations show that a partial ring current and an associated Region-2 type field-aligned current system exist in the magnetosphere of Jupiter. In the Earth's magnetosphere it is well known that the region-2 current system is created by the asymmetries imposed by a solar wind driven convection. Thus, we are getting first hints that the solar wind driven convection is important in Jupiter's magnetosphere as well. Other in-situ observations also point to dawn-dusk asymmetries imposed by the solar wind. For example, first order anisotropies in the Energetic Particle Detector show that the plasma is close to corotational on the dawn side but lags behind corotation in the dusk sector. Magnetic field data show that the current sheet is thin and highly organized on the dawn side but thick and disturbed on the dusk side. I will discuss the reasons why Brice and Ioannidis calculation may not be valid. I will show that both the magnetic field and plasma velocity estimates used by Brice and Ioannidis were rather excessive. Using more modern estimates of the field and velocity values I show that the solar wind convection can penetrate as deep as 40 RJ on the dawnside. I will present a new model of convection that invokes in addition to a distant neutral line spanning the whole magnetotail, a near

  7. AXIOM: Advanced X-Ray Imaging of the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Branduardi-Raymont, G.; Sembay, S. F.; Eastwood, J. P.; Sibeck, D. G.; Abbey, A.; Brown, P.; Carter, J. A.; Carr, C. M.; Forsyth, C.; Kataria, D.; Kemble, S.; Milan, S. E.; Owen, C. J.; Peacocke, L.; Read, A. M.; Coates, A. J.; Collier, M. R.; Cowley, S. W. H.; Fazakerley, A. N.; Fraser, G. W.; Jones, G. H.; Lallement, R.; Lester, M.; Porter, F. S.; Yeoman, T. K.

    2011-01-01

    Planetary plasma and magnetic field environments can be studied in two complementary ways by in situ measurements, or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Some parts of the Earth's magnetosphere have been remotely sensed, but the majority remains unexplored by this type of measurements. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques, which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth's magnetosphere. In this article we describe how an appropriately designed and located X-ray telescope, supported by simultaneous in situ measurements of the solar wind, can be used to image the dayside magnetosphere, magnetosheath and bow shock, with a temporal and spatial resolution sufficient to address several key outstanding questions concerning how the solar wind interacts with the Earth's magnetosphere on a global level. Global images of the dayside magnetospheric boundaries require vantage points well outside the magnetosphere. Our studies have led us to propose AXIOM: Advanced X-ray Imaging Of the Magnetosphere, a concept mission using a Vega launcher with a LISA Pathfinder-type Propulsion Module to place the spacecraft in a Lissajous orbit around the Earth Moon L1 point. The model payload consists of an X-ray Wide Field Imager, capable of both imaging and spectroscopy, and an in situ plasma and magnetic field measurement package. This package comprises a Proton-Alpha Sensor, designed to measure the bulk properties of the solar wind, an Ion Composition Analyser, to characterize the minor ion populations in the solar wind that cause charge exchange emission, and a Magnetometer, designed to measure the strength and direction

  8. AXIOM: Advanced X-ray Imaging of the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Branduardi-Raymont, G.; Sembay, S. F.; Eastwood, J. P.; Sibeck, D. G.; Abbey, A.; Brown, P.; Carter, J. A.; Carr, C. M.; Forsyth, C.; Kataria, D.; Kemble, S.; Milan, S. E.; Owen, C. J.; Peacocke, L.; Read, A. M.; Coates, A. J.; Collier, M. R.; Cowley, S. W. H.; Fazakerley, A. N.; Fraser, G. W.; Jones, G. H.; Lallement, R.; Lester, M.; Porter, F. S.; Yeoman, T. K.

    2012-01-01

    Planetary plasma and magnetic field environments can be studied in two complementary ways - by in situ measurements, or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Some parts of the Earth's magnetosphere have been remotely sensed, but the majority remains unexplored by this type of measurements. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques. which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth's magnetosphere. In this article we describe how an appropriately designed and located. X-ray telescope, supported by simultaneous in situ measurements of the solar wind, can be used to image the dayside magnetosphere, magnetosheath and bow shock. with a temporal and spatial resolution sufficient to address several key outstanding questions concerning how the solar wind interacts with the Earth's magnetosphere on a global level. Global images of the dayside magnetospheric boundaries require vantage points well outside the magnetosphere. Our studies have led us to propose 'AXIOM: Advanced X-ray Imaging Of the Magnetosphere', a concept mission using a Vega launcher with a LISA Pathfinder-type Propulsion Module to place the spacecraft in a Lissajous orbit around the Earth - Moon Ll point. The model payload consists of an X-ray Wide Field Imager, capable of both imaging and spectroscopy, and an in situ plasma and magnetic field measurement package. This package comprises a Proton-Alpha Sensor, designed to measure the bulk properties of the solar wind, an Ion Composition Analyser, to characterize the minor ion populations in the solar wind that cause charge exchange emission, and a Magnetometer, designed to measure the strength and

  9. Magnetospheric state of sawtooth events

    NASA Astrophysics Data System (ADS)

    Fung, Shing F.; Tepper, Julia A.; Cai, Xia

    2016-08-01

    Magnetospheric sawtooth events, first identified in the early 1990s, are named for their characteristic appearance of multiple quasiperiodic intervals of slow decrease followed by sharp increase of proton differential energy fluxes in the geosynchronous region. The successive proton flux oscillations have been interpreted as recurrences of stretching and dipolarization of the nightside geomagnetic field. Due to their often extended intervals with 2-10 cycles, sawteeth occurrences are sometimes referred to as a magnetospheric mode. While studies of sawtooth events over the past two decades have yielded a wealth of information about such events, the magnetospheric state conditions for the occurrence of sawtooth events and how sawtooth oscillations may depend on the magnetospheric state conditions remain unclear. In this study, we investigate the characteristic magnetospheric state conditions (specified by Psw interplanetary magnetic field (IMF) Btot, IMF Bz Vsw, AE, Kp and Dst, all time shifted with respect to one another) associated with the intervals before, during, and after sawteeth occurrences. Applying a previously developed statistical technique, we have determined the most probable magnetospheric states propitious for the development and occurrence of sawtooth events, respectively. The statistically determined sawtooth magnetospheric state has also been validated by using out-of-sample events, confirming the notion that sawtooth intervals might represent a particular global state of the magnetosphere. We propose that the "sawtooth state" of the magnetosphere may be a state of marginal stability in which a slight enhancement in the loading rate of an otherwise continuous loading process can send the magnetosphere into the marginally unstable regime, causing it to shed limited amount of energy quickly and return to the marginally stable regime with the loading process continuing. Sawtooth oscillations result as the magnetosphere switches between the marginally

  10. Magnetospheric State of Sawtooth Events

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Tepper, Julia A.; Cai, Xia

    2016-01-01

    Magnetospheric sawtooth events, first identified in the early 1990s, are named for their characteristic appearance of multiple quasiperiodic intervals of slow decrease followed by sharp increase of proton differential energy fluxes in the geosynchronous region. The successive proton flux oscillations have been interpreted as recurrences of stretching and dipolarization of the nightside geomagnetic field. Due to their often extended intervals with 210 cycles, sawteeth occurrences are sometimes referred to as a magnetospheric mode. While studies of sawtooth events over the past two decades have yielded a wealth of information about such events, the magnetospheric state conditions for the occurrence of sawtooth events and how sawtooth oscillations may depend on the magnetospheric state conditions remain unclear. In this study, we investigate the characteristic magnetospheric state conditions (specified by Psw interplanetary magnetic field (IMF) Btot, IMF Bz Vsw, AE, Kp and Dst, all time shifted with respect to one another) associated with the intervals before, during, and after sawteeth occurrences. Applying a previously developed statistical technique, we have determined the most probable magnetospheric states propitious for the development and occurrence of sawtooth events, respectively. The statistically determined sawtooth magnetospheric state has also been validated by using out-of-sample events, confirming the notion that sawtooth intervals might represent a particular global state of the magnetosphere. We propose that the sawtooth state of the magnetosphere may be a state of marginal stability in which a slight enhancement in the loading rate of an otherwise continuous loading process can send the magnetosphere into the marginally unstable regime, causing it to shed limited amount of energy quickly and return to the marginally stable regime with the loading process continuing. Sawtooth oscillations result as the magnetosphere switches between the marginally

  11. Modeling ionospheric electron precipitation due to wave particle scattering in the magnetosphere and the feedback effect on the magnetospheric dynamics

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Jordanova, V.; Ridley, A. J.; Albert, J.; Horne, R. B.; Jeffery, C. A.

    2015-12-01

    Electron precipitation down to the atmosphere caused by wave-particle scattering in the magnetosphere contribute significantly to the enhancement of auroral ionospheric conductivity. Global MHD models that are incapable of capturing kinetic physics in the inner magnetosphere usually adopt MHD parameters to specify the precipitation flux to estimate auroral conductivity, hence losing self-consistency in the global circulation of the magnetosphere-ionosphere system. In this study we improve the coupling structure in global models by connecting the physics-based (wave-particle scattering) electron precipitation with the ionospheric electrodynamics and investigate the feedback effect on the magnetospheric dynamics. We use BATS-R-US coupled with a kinetic ring current model RAM-SCB that solves pitch angle dependent particle distributions to study the global circulation dynamics during the Jan 25-26, 2013 storm event. Following tail injections, we found enhanced precipitation number and energy fluxes of tens of keV electrons being scattered into loss cone due to interactions with enhanced chorus and hiss waves in the magnetosphere. This results in a more profound auroral conductance and larger electric field imposing on the plasma transport in the magnetosphere. We also compared our results with previous methods in specifying the auroral conductance, such as empirical relation used in Ridley et al. (2004). It is found that our physics-based method develops a larger convection electric field in the near-Earth region and therefore leads to a more intense ring current.

  12. Solar wind entry into the high-latitude terrestrial magnetosphere during geomagnetically quiet times.

    PubMed

    Shi, Q Q; Zong, Q-G; Fu, S Y; Dunlop, M W; Pu, Z Y; Parks, G K; Wei, Y; Li, W H; Zhang, H; Nowada, M; Wang, Y B; Sun, W J; Xiao, T; Reme, H; Carr, C; Fazakerley, A N; Lucek, E

    2013-01-01

    An understanding of the transport of solar wind plasma into and throughout the terrestrial magnetosphere is crucial to space science and space weather. For non-active periods, there is little agreement on where and how plasma entry into the magnetosphere might occur. Moreover, behaviour in the high-latitude region behind the magnetospheric cusps, for example, the lobes, is poorly understood, partly because of lack of coverage by previous space missions. Here, using Cluster multi-spacecraft data, we report an unexpected discovery of regions of solar wind entry into the Earth's high-latitude magnetosphere tailward of the cusps. From statistical observational facts and simulation analysis we suggest that these regions are most likely produced by magnetic reconnection at the high-latitude magnetopause, although other processes, such as impulsive penetration, may not be ruled out entirely. We find that the degree of entry can be significant for solar wind transport into the magnetosphere during such quiet times.

  13. Magnetospheric Convection as a Global Force Phenomenon

    NASA Astrophysics Data System (ADS)

    Siscoe, G.

    2007-12-01

    Since 1959 when Thomas Gold showed that motions in the magnetosphere were possible despite plasma being frozen to the magnetic field, magnetospheric convection as a subject of study has gone through several stages (to be reviewed) leading to a recent one that integrates convection into a global system of balance of forces. This area of research has opened by focusing on the region 1 current system as a carrier of force between the solar wind and the ionosphere/thermosphere fluid. An important result to emerge from it is the realization that the force that the solar wind delivers to the magnetosphere in being transferred by the region 1 current system to the ionosphere/thermosphere fluid is amplified by about an order of magnitude. (Vasyliunas refers to this as "leveraging.") The apparent violation of Newton's Third Law results from the main participants in the force balance being not the solar wind force but the JxB force on the ionosphere/thermosphere fluid and the mu-dot-grad-B force on the Earth's dipole. This talk extends the study by considering the global force-balance problem separately for the Pedersen current (a completion of the region 1 problem), the Hall current (thus introducing the region 2 current system), and the Cowling current (bringing in the substorm current wedge). The approach is through representing the ionosphere/thermosphere fluid by the shallow water equations. Novelties that result include force balance by means of tidal bulges and tidal bores.

  14. Energetic Nitrogen Ions within the Inner Magnetosphere of Saturn

    NASA Astrophysics Data System (ADS)

    Sittler, E. C.; Johnson, R. E.; Richardson, J. D.; Jurac, S.; Moore, M.; Cooper, J. F.; Mauk, B. H.; Smith, H. T.; Michael, M.; Paranicus, C.; Armstrong, T. P.; Tsurutani, B.; Connerney, J. E. P.

    2003-05-01

    Titan's interaction with Saturn's magnetosphere will result in the energetic ejection of atomic nitrogen atoms into Saturn's magnetosphere due to dissociation of N2 by electrons, ions, and UV photons. The ejection of N atoms into Saturn's magnetosphere will form a nitrogen torus around Saturn with mean density of about 4 atoms/cm3 with source strength of 4.5x1025 atoms/sec. These nitrogen atoms are ionized by photoionization, electron impact ionization and charge exchange reactions producing an N+ torus of 1-4 keV suprathermal ions centered on Titan's orbital position. We will show Voyager plasma observations that demonstrate presence of a suprathermal ion component within Saturn's outer magnetosphere. The Voyager LECP data also reported the presence of inward diffusing energetic ions from the outer magnetosphere of Saturn, which could have an N+ contribution. If so, when one conserves the first and second adiabatic invariant the N+ ions will have energies in excess of 100 keV at Dione's L shell and greater than 400 keV at Enceladus' L shell. Energetic charged particle radial diffusion coefficients are also used to constrain the model results. But, one must also consider the solar wind as another important source of keV ions, in the form of protons and alpha particles, for Saturn's outer magnetosphere. Initial estimates indicate that a solar wind source could dominate in the outer magnetosphere, but various required parameters for this estimate are highly uncertain and will have to await Cassini results for confirmation. We show that satellite sweeping and charged particle precipitation within the middle and outer magnetosphere will tend to enrich N+ ions relative to protons within Saturn's inner magnetosphere as they diffuse radially inward for radial diffusion coefficients that do not violate observations. Charge exchange reactions within the inner magnetosphere can be an important loss mechanism for O+ ions, but to a lesser degree for N+ ions. Initial LECP

  15. Magnetic reconnection, merging, and viscous interaction in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Heikkila, W. J.

    1990-01-01

    This paper discusses the historical development of the reconnection theory, with consideration given to the effects of a magnetic field within the plasma and the mechanisms of magnetic reconnection, merging, and viscouslike interaction. Particular attention is given to Dungey's (1958, 1961) steady-state reconnection model of the magnetosphere and to its criticism. Observational evidence supporting the reconnection model is presented.

  16. Electrostatic waves and the strong diffusion of magnetospheric electrons

    NASA Technical Reports Server (NTRS)

    Kennel, C. F.; Ashour-Abdalla, M.

    1982-01-01

    A comprehensive review of electron pitch angle scattering in the magnetosphere and the plasma waves responsible for it is presented, emphasizing the strong diffusion of diffuse auroral electrons by electrostatic electron cyclotron harmonic waves. The weak diffusion of energetic radiation belt electrons within the plasmasphere is reviewed briefly. Several new suggestions concerning the quasilinear diffusion from and saturation of electrostatic waves are included.

  17. Overview of laser technology at Los Alamos National Laboratory

    NASA Astrophysics Data System (ADS)

    Lewis, G. K.; Cremers, D. A.

    Los Alamos National Laboratory has had a long history of involvement in laser sciences and has been recognized both for its large laser programs and smaller scale developments in laser technology and applications. The first significant program was with the Rover nuclear-based rocket propulsion system in 1968 to study laser initiated fusion. From here applications spread to programs in laser isotope separation and development of large lasers for fusion. These programs established the technological human resource base of highly trained laser physicists, engineers, and chemists that remain at the Laboratory today. Almost every technical division at Los Alamos now has some laser capability ranging from laser development, applications, studies on nonlinear processes, modeling and materials processing. During the past six years over eight R&D-100 Awards have been received by Los Alamos for development of laser-based techniques and instrumentation. Outstanding examples of technology developed include LIDAR applications to environmental monitoring, single molecule detection using fluorescence spectroscopy, a laser-based high kinetic energy source of oxygen atoms produced by a laser-sustained plasma, laser-induced breakdown spectroscopy (LIBS) for compositional, analysis, thin film high temperature superconductor deposition, multi-station laser welding, and direct metal deposition and build-up of components by fusing powder particles with a laser beam.

  18. Overview of laser technology at Los Alamos National Laboratory

    SciTech Connect

    Lewis, G.K.; Cremers, D.A.

    1994-09-01

    Los Alamos National Laboratory has had a long history of involvement in laser sciences and has been recognized both for its large laser programs and smaller scale developments in laser technology and applications. The first significant program was with the Rover nuclear-based rocket propulsion system in 1968 to study laser initiated fusion. From here applications spread to programs in laser isotope separation and development of large lasers for fusion. These programs established the technological human resource base of highly trained laser physicists, engineers, and chemists that remain at the Laboratory today. Almost every technical division at Los Alamos now has some laser capability ranging from laser development, applications, studies on nonlinear processes, modeling and materials processing. During the past six years over eight R&D-100 Awards have been received by Los Alamos for development of laser-based techniques and instrumentation. Outstanding examples of technology developed include LIDAR applications to environmental monitoring, single molecule detection using fluorescence spectroscopy, a laser-based high kinetic energy source of oxygen atoms produced by a laser-sustained plasma, laser-induced breakdown spectroscopy (LIBS) for compositional, analysis, thin film high temperature superconductor deposition, multi-station laser welding, and direct metal deposition and build-up of components by fusing powder particles with a laser beam.

  19. Los Alamos PC estimating system

    SciTech Connect

    Stutz, R.A.; Lemon, G.D.

    1987-01-01

    The Los Alamos Cost Estimating System (QUEST) is being converted to run on IBM personal computers. This very extensive estimating system is capable of supporting cost estimators from many different and varied fields. QUEST does not dictate any fixed method for estimating. QUEST supports many styles and levels of detail estimating. QUEST can be used with or without data bases. This system allows the estimator to provide reports based on levels of detail defined by combining work breakdown structures. QUEST provides a set of tools for doing any type of estimate without forcing the estimator to use any given method. The level of detail in the estimate can be mixed based on the amount of information known about different parts of the project. The system can support many different data bases simultaneously. Estimators can modify any cost in any data base.

  20. Saturn's Magnetosphere, Rings, and Inner Satellites.

    PubMed

    VAN Allen, J A; Thomsen, M F; Randall, B A; Rairden, R L; Grosskreutz, C L

    1980-01-25

    Our 31 August to 5 September 1979 observations together with those of the other Pioneer 11 investigators provide the first credible discovery of the magnetosphere of Saturn and many detailed characteristics thereof. In physical dimensions and energetic charged particle population, Saturn's magnetosphere is intermediate between those of Earth and Jupiter. In terms of planetary radii, the scale of Saturn's magnetosphere more nearly resembles that of Earth and there is much less inflation by entrapped plasma than in the case at Jupiter. The orbit of Titan lies in the outer fringes of the magnetosphere. Particle angular distributions on the inbound leg of the trajectory (sunward side) have a complex pattern but are everywhere consistent with a dipolar magnetic field approximately perpendicular to the planet's equator. On the outbound leg (dawnside) there are marked departures from this situation outside of 7 Saturn radii (Rs), suggesting an equatorial current sheet having both longitudinal and radial components. The particulate rings and inner satellites have a profound effect on the distribution of energetic particles. We find (i) clear absorption signatures of Dione and Mimas; (ii) a broad absorption region encompassing the orbital radii of Tethys and Enceladus but probably attributable, at least in part, to plasma physical effects; (iii) no evidence for Janus (1966 S 1) (S 10) at or near 2.66 Rs; (iv) a satellite of diameter greater, similar 170 kilometers at 2.534 R(s) (1979 S 2), probably the same object as that detected optically by Pioneer 11 (1979 S 1) and previously by groundbased telescopes (1966 S 2) (S 11); (v) a satellite of comparable diameter at 2.343 Rs (1979 S 5); (vi) confirmation of the F ring between 2.336 and 2.371 Rs; (vii) confirmation of the Pioneer division between 2.292 and 2.336 Rs; (viii) a suspected satellite at 2.82 Rs (1979 S 3); (ix) no clear evidence for the E ring though its influence may be obscured by stronger effects; and (x) the

  1. Light ion concentrations in Jupiter's inner magnetosphere

    NASA Technical Reports Server (NTRS)

    Tokar, R. L.; Gurnett, D. A.; Shaw, R. R.; Bagenal, F.

    1982-01-01

    The light ion distribution in the inner Jovian magnetosphere is investigated using whistler dispersion measurements from the Voyager 1 plasma wave instrument and heavy ion plasma concentrations from the plasma instrument. Two models are developed for the light ion concentration over 14 L shells between L = 5.2 and 6.2, one giving a constant concentration along the field line and the other corresponding to an exponential density distribution. Due to heavy ion concentrations near the equator that are typically an order of magnitude larger than the light ion concentration, results obtained are mainly relevant to the light ion concentration outside of the torus. Light ion concentration near the equator ranges from about 1-10% of the heavy ion concentration, while outside the torus the light ions are the dominant species.

  2. The Inclination Angle and Evolution of the Braking Index of Pulsars with Plasma-filled Magnetosphere: Application to the High Braking Index of PSR J1640-4631

    NASA Astrophysics Data System (ADS)

    Ekşi, K. Y.; Andaç, I. C.; Çıkıntoğlu, S.; Gügercinoğlu, E.; Vahdat Motlagh, A.; Kızıltan, B.

    2016-05-01

    The recently discovered rotationally powered pulsar PSR J1640-4631 is the first to have a braking index measured, with high enough precision, that is greater than 3. An inclined magnetic rotator in vacuum or plasma would be subject not only to spin-down but also to an alignment torque. The vacuum model can address the braking index only for an almost orthogonal rotator, which is incompatible with the single-peaked pulse profile. The magnetic dipole model with the corotating plasma predicts braking indices between 3 and 3.25. We find that the braking index of 3.15 is consistent with two different inclination angles, 18.°5 ± 3° and 56° ± 4°. The smaller angle is preferred given that the pulse profile has a single peak and the radio output of the source is weak. We infer the change in the inclination angle to be at the rate -0.°23 per century, three times smaller in absolute value than the rate recently observed for the Crab pulsar.

  3. Initial results on positron confinement in a magnetospheric configuration

    NASA Astrophysics Data System (ADS)

    Saitoh, Haruhiko; Yoshida, Zensho; Yano, Yoshihisa; Morikawa, Junji

    2011-10-01

    Creation of positron-electron plasma in a laboratory is an interesting and challenging subject, which may open many scientific applications. Although single-component plasma is stably confined in linear traps, for example Penning-Malmberg trap, it is not straightforward to simultaneously confine electrons and positrons as plasma. Toroidal geometries have advantages for solving this problem. For this purpose, studies on toroidal non-neutral plasma have been conducted in the levitated magnetospheric configuration, RT-1. Stable confinement and self-organization of toroidal non-neutral plasma was realized in RT-1; rigid-rotating pure electron plasma is confined for more than 300s [Z. Yoshida et al., PRL 104, 235004 (2010)]. As the initial step toward the formation of magnetospheric antimatter plasmas, we installed a 1MBq Na-22 radiation source in RT-1. Annihilation gamma-rays were observed by a NaI(TI) scintillator detector, for the estimation of basic injection and confinement properties of positrons in the magnetospheric configuration. Numerical analysis of positron orbits in RT-1 and the initial experimental results will be presented. Work funded by MEXT of Japan (23224014, 23654201).

  4. Unresolved Issues With Inner Magnetosphere-Ionosphere Coupling

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Khazanov, G.

    2004-01-01

    Dipolarization and the release of stored magnetic energy is strongly evident in the energized plasma sheet electrons and ions injected earthward from the magnetotail. While some of these plasma are presumed lost into the dayside magnetosheath, much of the energy is dissipated into the ionosphere through electric currents, through collisions into low energy plasma, and into plasma waves, which then go on to heat and energize plasma of the inner magnetosphere. Many mechanisms for the transfer of energy and the consequences to inner magnetospheric plasma populations have been proposed. The sophistication of theoretical models to represent the interdependencies between plasma populations is rapidly increasing. However without the restraint and reality imposed on theory by relevant measurements, the degree to which specific mechanisms participate in the exchange of energy as a function of location and time cannot be known. ORBITALS offers this capability. Some of the outstanding problems in inner magnetospheric physics and the opportunities presented by the ORBITAL concept to solve problems will be discussed.

  5. Black hole magnetospheres

    SciTech Connect

    Nathanail, Antonios; Contopoulos, Ioannis

    2014-06-20

    We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.

  6. Transport of magnetic flux in Saturn’s inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Russell, Christopher T.; Lai, H. R.; Wei, H. Y.; Jia, Y. D.; Dougherty, M. K.

    2015-11-01

    The dynamics of the Saturnian magnetosphere, which rotates rapidly with an internal plasma source provided by Enceladus, qualitatively resembles those of the jovian magnetosphere powered by Io. The newly added plasma is accelerated to the corotation speed and moves outward together with the magnetic flux. In the near tail region, reconnection cuts the magnetic flux, reconnects it into plasma-depleted inward moving flux tubes and outward moving massive plasmoids. The buoyant empty tubes then convect inward against the outward flow to conserve the total magnetic flux established by the internal dynamo. In both jovian and saturnian magnetospheres, flux tubes with enhanced field strength relative to their surroundings are detected in the equatorial region. Recent observations show that there are flux tubes with reduced field strength off the equator in the saturnian magnetosphere. To understand the formation mechanism of both types of flux tubes, we have surveyed all the available 1-sec magnetic field data from Cassini. The systematic statistical study confirms the different latitudinal distributions of the two types of flux tubes. In addition, enhanced-field flux tubes are closer to the planet while reduced-field flux tubes can be detected at larger distances; both types of flux tubes become indistinguishable from the background magnetic flux inside an L-value of about 4; the local time distribution of both types of flux tubes are similar and they contain about the same amount of magnetic flux. Therefore, the two types of flux tubes are the same phenomena with different manifestations in different plasma environments. When the surrounding plasma density is high (near the equator and closer to the plasma source region), the flux tubes are compressed and have enhanced field strength inside; while in the low-plasma density region (off the equator and further from the plasma source region), the flux tubes expand and have reduced field strength inside.

  7. On the Magnetospheric Engine Behind Kilometric Radiation at Earth and Saturn

    NASA Astrophysics Data System (ADS)

    Brandt, Pontus; Mitchell, Donald

    2014-05-01

    The planets of the solar system display a range of different space environments and solar interaction regimes, from non/weakly magnetized, to magnetized with convective- versus rotation-dominated magnetospheres. All magnetized planets with an appreciable magnetosphere are immersed in a dynamic energetic particle (hot plasma), as well as cold plasma, environment. These five planetary magnetospheres (Earth, Jupiter, Saturn, Uranus and Neptune) are also significant emitters of low-frequency radio waves that are consistent with a cyclotron-maser instability set up in a field-aligned current region. Radio observations in the <200 MHz range is so far the only technique that shows promise to provide constraints on the magnetospheric processes of exoplanets and their stellar-wind interaction. The thrust of this presentation is therefore to understand the relation between radio emissions and magnetospheric acceleration processes in our own solar system as a laboratory to determine what remote radio observations of exoplanets may tell us about magnetospheric processes. Terrestrial Auroral Kilometric Radiation (AKR) emissions in the ~30-800 kHz range have long been known to be associated with auroral intensifications and magnetospheric substorms. In a similar fashion, recent remote imaging using Energetic Neutral Atoms (ENAs) obtained by the Cassini mission have revealed that the periodic Saturn Kilometric Radiation (SKR) emission from Saturn's high-latitude magnetosphere is highly correlated with simultaneous large-scale injections of energetic particles in the night side magnetosphere. These observations imply that the engine behind the AKR and SKR is current system associated with the planet ward fast plasma flows during an injection and/or the resulting plasma pressure gradients of the heated plasma.

  8. Width of Injection/Dispersion Events in Saturn's Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Hill, T. W.

    2008-05-01

    Longitudinally localized injection and drift dispersion of hot plasma are frequently observed by the Cassini Plasma Spectrometer (CAPS) and the Cassini Magnetospheric Imaging Instrument (MIMI) in Saturn's magnetosphere. These signatures provide direct evidence for the major convective process in the inner magnetosphere of a rapidly rotating planet, in which the radial transport of plasma is expected to comprise hot, tenuous plasma moving inward and cooler, denser plasma moving outward. Previous analyses of Cassini plasma observations are consistent with this scenario, but suggest further that the hot inflow sectors are significantly narrower than the adjacent cooler outflow sectors, a property that was not anticipated theoretically. Here we quantify this property by calculating the fraction of the available time that is occupied by injection structures in a two-year data set containing 429 such structures. This fraction is found to be small, typically ~ 3 - 7%, with no obvious dependence on SKR longitude. We will expand our data set by including the very young injection events discussed by Burch et al. [2005 GRL], which were excluded by the selection criteria in our previous study.

  9. A pincer-shaped plasma sheet at Uranus

    NASA Technical Reports Server (NTRS)

    Hammond, C. Max; Walker, Raymond J.; Kivelson, Margaret G.

    1990-01-01

    An MHD simulation of the terrestrial magnetosphere, rescaled to represent the Uranian magnetotail, is carried out. The 3p immersion can be explained in terms of possible extreme departures from average plasma sheet shapes in the Uranian magnetosphere. The orientation of the Uranian dipole and rotation axes produce a dynamically curved plasma sheet which is an unusual feature of the Uranian magnetosphere.

  10. Current Understanding of Mercury's Magnetosphere before MESSENGER

    NASA Astrophysics Data System (ADS)

    Krimigis, S. M.

    The MESSENGER spacecraft is scheduled to be launched mid-May, 2004 on a trajectory that includes two flybys (October 07, July 08) and eventual orbit insertion in July 2009 around the planet Mercury. Embedded in its payload are instruments to examine the basic properties of the planet's magnetosphere, including magnetometer, plasma, and energetic particle measurements (Gold et al, 2001). Our present knowledge of Mercury's magnetosphere is derived from two nightside Mariner 10 flybys in 1974, 1975 that established the presence of an intrinsic magnetic field and some energetic particles. Unfortunately not even the magnetic dipole term was well-resolved, and the fluxes and identity of energetic particles have been a subject of extensive discussion and varying interpretations (e.g. Armstrong et al, 1975, Christon, 1989). There has been evidence of field-aligned currents (e.g. Slavin et al, 1997), but alternative interpretations of magnetic signatures suggest that the magnetosphere may be driven by changing external boundary conditions (Luhman et al, 1998). These uncertainties, coupled with the observed presence of volatiles (H, He, O, Na, K, Ca) raise obvious questions on current closure, hot plasma injection and acceleration, the frequency with which the planetary surface is exposed to the solar wind, and potential sputtering of material due to particle impingement on the regolith. The talk will review our current knowledge and describe the measurements expected from MESSENGER that will address some of the key science questions. Armstrong et al, JGR, 80, 4015, 1975 Gold et al, Planet and Space Sci, 49, 1467, 2001 Christon, S.P., JGR, 94, 6481, 1989 Slavin et al, Planet and Space Sci, 45, 133, 1997 Luhman et al, JGR, 103, 9113, 1998

  11. Numerical simulation of injection/dispersion events in Saturn's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Liu, X.

    2013-05-01

    In Saturn's rotation-driven magnetosphere, radial transport of plasma occurs through a time-variable pattern of wider outflow channels containing cool, dense plasma from interior sources, alternating with narrower inflow channels containing hot, tenuous plasma from the outer magnetosphere. This pattern is evident in the results of numerical simulations using the Rice Convection Model, including a broadly distributed, continuously active source of cool plasma and the effects of the associated pick-up current, along with the centrifugal and Coriolis forces and the pressure-gradient force. We have recently incorporated a source of hot, tenuous plasma at the outer simulation boundary, and have successfully simulated the V-shaped injection/dispersion signatures in linear energy-time spectrograms that are observed by the Cassini Plasma Spectrometer (CAPS) on every pass through the inner magnetosphere. These drift dispersion signatures are the "smoking gun" of the centrifugally driven interchange transport process.

  12. Empirical magnetospheric and ionospheric models: legacy and outlook

    NASA Astrophysics Data System (ADS)

    Vassiliadis, D.

    2011-12-01

    Complex geospace plasmas have, by definition, a large number of dynamical regimes where the development of empirical models from experimental data is crucial. In the magnetosphere and ionosphere, the ongoing collection of in situ measurements has led to empirical models of various types. This paper reviews a small number of recent models and presents new approaches in constructing empirical models. Starting with the outer magnetosphere and high-latitude ionosphere, the magnetic field has been modeled in terms of static and time-dependent approximations, including time-dependent interplanetary driver variables. For the surface field in particular, a number of special approximations are possible leading to separation into different activity types and current systems. In the inner magnetosphere, models of the relativistic-electron flux have been constructed, together with ULF-wave-power models. Once more, interplanetary variables, such as the plasma velocity, have been included as necessary drivers of the flux and wave-power activity especially at the geosynchronous region. In the above cases, the models provide temporal scales and spatial extent of the geospace disturbance. It is shown that the magnetospheric and ionospheric plasmas respond in one or more characteristic modes whose spatiotemporal and energy characteristics are defined. We compare these empirical modeling approaches with numerical simulations and discuss their relative advantages. As ongoing and new missions yield additional observations from different locations and energy ranges, empirical models will be used for an increasing number of applications.

  13. Concepts and Results of New Method for Accurate Ground and In-Flight Calibration of the Particle Spectrometers of the Fast Plasma Investigation on NASA's Magnetospheric MultiScale Mission

    NASA Astrophysics Data System (ADS)

    Gliese, U.; Gershman, D. J.; Dorelli, J.; Avanov, L. A.; Barrie, A. C.; Clark, G. B.; Kujawski, J. T.; Mariano, A. J.; Coffey, V. N.; Tucker, C. J.; Chornay, D. J.; Cao, N. T.; Zeuch, M. A.; Dickson, C.; Smith, D. L.; Salo, C.; MacDonald, E.; Kreisler, S.; Jacques, A. D.; Giles, B. L.; Pollock, C. J.

    2015-12-01

    The Fast Plasma Investigation (FPI) on NASA's Magnetospheric MultiScale (MMS) mission employs 16 Dual Electron Spectrometers and 16 Dual Ion Spectrometers with 4 of each type on each of 4 spacecraft to enable fast (30 ms for electrons; 150 ms for ions) and spatially differentiated measurements of the full 3D particle velocity distributions. This approach presents a new and challenging aspect to the calibration and operation of these instruments on ground and in flight. The response uniformity, the reliability of their calibration and the approach to handling any temporal evolution of these calibrated characteristics all assume enhanced importance in this application, where we attempt to understand the meaning of particle distributions within the ion and electron diffusion regions of magnetically reconnecting plasmas. We have developed a detailed model of the spectrometer detection system, its behavior and its signal, crosstalk and noise sources. Based on this, we have devised a new calibration method that enables accurate and repeatable measurement of micro-channel plate (MCP) gain, signal loss due to variation in MCP gain and crosstalk effects in one single measurement. The foundational concepts of this new calibration method, named threshold scan, are presented. It is shown how this method has been successfully applied both on ground and in-flight to achieve highly accurate and precise calibration of all 64 spectrometers. Calibration parameters that will evolve in flight are determined daily providing a robust characterization of sensor suite performance, as a basis for both in-situ hardware adjustment and data processing to scientific units, throughout mission lifetime. This is shown to be very desirable as the instruments will produce higher quality raw science data that will require smaller post-acquisition data-corrections using results from in-flight derived pitch angle distribution measurements and ground calibration measurements. The practical application

  14. The Magnetospheric Multiscale Constellation

    NASA Astrophysics Data System (ADS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2016-03-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  15. Magnetosphere of Uranus

    SciTech Connect

    Ness, N.F.

    1986-12-01

    The magnetosphere and magnetic field of Uranus are analyzed using Voyager 2 data. It is observed that the magnetic axis of Uranus is tilted 60 deg from its rotation axis; the magnetic dipole center is displaced almost 7700 km from the center of the planet; the magnetic field intensity varies over its surface between 24,000-69,000 gammas; and the rotation rate of the planet is 17.24 hours. The dynamo generation of the planetary magnetic field is examined. Consideration is given to the auroral activity, magnetic tails, moons, and radiation belts of charged particles of Uranus. The significance of the large tilt and offset magnetic axis for the interior of Uranus is discussed.

  16. The Extended Pulsar Magnetosphere

    NASA Technical Reports Server (NTRS)

    Constantinos, Kalapotharakos; Demosthenes, Kazanas; Ioannis, Contopoulos

    2012-01-01

    We present the structure of the 3D ideal MHD pulsar magnetosphere to a radius ten times that of the light cylinder, a distance about an order of magnitude larger than any previous such numerical treatment. Its overall structure exhibits a stable, smooth, well-defined undulating current sheet which approaches the kinematic split monopole solution of Bogovalov 1999 only after a careful introduction of diffusivity even in the highest resolution simulations. It also exhibits an intriguing spiral region at the crossing of two zero charge surfaces on the current sheet, which shows a destabilizing behavior more prominent in higher resolution simulations. We discuss the possibility that this region is physically (and not numerically) unstable. Finally, we present the spiral pulsar antenna radiation pattern.

  17. Sunset at the ALaMO

    NASA Video Gallery

    A new color all-sky camera has opened its eyes at the ALaMO, or Automated Lunar and Meteor Observatory, at NASA's Marshall Space Flight Center in Huntsville, Ala. Watch its inaugural video below, s...

  18. Publications of Los Alamos research 1988

    SciTech Connect

    Varjabedian, K.; Dussart, S.A.; McClary, W.J.; Rich, J.A.

    1989-12-01

    This bibliography lists unclassified publications of work done at the Los Alamos National Laboratory for 1988. The entries, which are subdivided by broad subject categories, are cross-referenced with an author index and a numeric index.

  19. Environmental surveillance at Los Alamos during 1994

    SciTech Connect

    1996-07-01

    This report describes environmental monitoring activities at Los Alamos National Laboratory for 1994. Data were collected to assess external penetrating radiation, airborne emissions, liquid effluents, radioactivity of environmental materials and food stuffs, and environmental compliance.

  20. New Rad Lab for Los Alamos

    ScienceCinema

    None

    2016-07-12

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  1. New Rad Lab for Los Alamos

    SciTech Connect

    2008-08-06

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  2. Views of Earth's magnetosphere with the image satellite.

    PubMed

    Burch, J L; Mende, S B; Mitchell, D G; Moore, T E; Pollock, C J; Reinisch, B W; Sandel, B R; Fuselier, S A; Gallagher, D L; Green, J L; Perez, J D; Reiff, P H

    2001-01-26

    The IMAGE spacecraft uses photon and neutral atom imaging and radio sounding techniques to provide global images of Earth's inner magnetosphere and upper atmosphere. Auroral imaging at ultraviolet wavelengths shows that the proton aurora is displaced equatorward with respect to the electron aurora and that discrete auroral forms at higher latitudes are caused almost completely by electrons. Energetic neutral atom imaging of ions injected into the inner magnetosphere during magnetospheric disturbances shows a strong energy-dependent drift that leads to the formation of the ring current by ions in the several tens of kiloelectron volts energy range. Ultraviolet imaging of the plasmasphere has revealed two unexpected features-a premidnight trough region and a dayside shoulder region-and has confirmed the 30-year-old theory of the formation of a plasma tail extending from the duskside plasmasphere toward the magnetopause.

  3. Magnetosphere, rings, and moons of Uranus

    SciTech Connect

    Cheng, A.F.

    1984-10-01

    The observation of an ultraviolet aurora on Uranus implies the existence of a magnetosphere. It is suggested that the magnetospheres of Uranus and Saturn may be very similar. Charged particle sputtering of water ice surfaces on the Uranian moons may maintain an oxygen ion plasma torus similar to the heavy ion plasma torus at Saturn. Atmospheric cosmic ray albedo neutron decay may sustain an inner radiation belt with omnidirectional proton fluxes. If the 100 keV ion fluxes near 7 RU are similar to Saturnian ion fluxes at such energies, the Uranian aurora may be maintained by ion precipitation from the radiation belts at nearly the strong diffusion rate. This mechanism predicts comparable aurorae over both magnetic poles of Uranus, in contrast with the Faraday disc dynamo mechanism, which powers an aurora only over the sunlit pole of uranus. If, however, the 100 kev ion fluxes at Uranus are comparable to those at Saturn, any exposed methane ice surfaces on the moons and rings of Uranus would be quickly transformed by ion impacts to a black, carbonaceous polymer.

  4. EMIC Waves in the Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Usanova, M.; Mann, I. R.; Drozdov, A.; Orlova, K.; Shprits, Y.; Darrouzet, F.; Ergun, R.

    2015-12-01

    Electromagnetic ion cyclotron (EMIC) wave excitation in the inner magnetosphere has been the focus of extensive study over the past few decades, not only because of the role played by EMIC waves in ring current dynamics but also because of their potential importance for scattering radiation belt electrons into the atmosphere. Theory predicts that regions of enhanced cold dense plasma density embedded in relatively low background magnetic field (such as the outer equatorial plasmasphere or plasmaspheric plumes) should aid EMIC wave growth. Also, enhanced plasma density lowers the energy threshold for the resonant pitch angle scattering of outer radiation belt electrons such that EMIC waves can interact with electrons with energies below 1 MeV and hence could be a potentially important radiation belt loss mechanism. EMIC wave normal angle and polarization are also important properties that control the efficiency of their interaction with energetic particles. We will review recent statistical and single-event studies and focus on new understanding of EMIC wave characteristics and generation mechanisms in the inner equatorial magnetosphere - information extremely important for understanding energetic particle dynamics and in particular, for radiation belt and ring current modeling.

  5. Magnetosphere, Rings, and Moons of Uranus

    NASA Technical Reports Server (NTRS)

    Cheng, A. F.

    1984-01-01

    The observation of an ultraviolet aurora on Uranus implies the existence of a magnetosphere. It is suggested that the magnetospheres of Uranus and Saturn may be very similar. Charged particle sputtering of water ice surfaces on the Uranian moons may maintain an oxygen ion plasma torus similar to the heavy ion plasma torus at Saturn. Atmospheric cosmic ray albedo neutron decay may sustain an inner radiation belt with omnidirectional proton fluxes. If the 100 keV ion fluxes near 7 RU are similar to Saturnian ion fluxes at such energies, the Uranian aurora may be maintained by ion precipitation from the radiation belts at nearly the strong diffusion rate. This mechanism predicts comparable aurorae over both magnetic poles of Uranus, in contrast with the Faraday disc dynamo mechanism, which powers an aurora only over the sunlit pole of uranus. If, however, the 100 kev ion fluxes at Uranus are comparable to those at Saturn, any exposed methane ice surfaces on the moons and rings of Uranus would be quickly transformed by ion impacts to a black, carbonaceous polymer.

  6. Edward Teller Returns to LOS Alamos

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.

    2010-01-01

    I was asked to share some reflections of Edward Teller's return to Los Alamos during my directorship. I met Teller late in his life. My comments focus on that time and they will be mostly in the form of stories of my interactions and those of my colleagues with Teller. Although the focus of this symposium is on Teller's contributions to science, at Los Alamos it was never possible to separate Teller's science from policy and controversy ...

  7. Internship at Los Alamos National Laboratory

    SciTech Connect

    Dunham, Ryan Q.

    2012-07-11

    Los Alamos National Laboratory (LANL) is located in Los Alamos, New Mexico. It provides support for our country's nuclear weapon stockpile as well as many other scientific research projects. I am an Undergraduate Student Intern in the Systems Design and Analysis group within the Nuclear Nonproliferation division of the Global Security directorate at LANL. I have been tasked with data analysis and modeling of particles in a fluidized bed system for the capture of carbon dioxide from power plant flue gas.

  8. Global Magnetospheric Modeling of 3D Reconnection

    NASA Technical Reports Server (NTRS)

    Spicer, Daniel S.

    1999-01-01

    A review of approaches to the global modeling of the terrestrial magnetosphere, how these approaches are utilized to interpret satellite data, and how these approaches have been successful at predicting magnetospheric phenomena will be presented. In addition, the importance of the ionospheric boundary and its effect on the globally topology of the magnetospheric magnetic field will be reviewed. In particular, numerical results that are rapidly changing our view of magnetospheric reconnection within the magnetospheric magnetic field will be discussed.

  9. Los Alamos Laser Eye Investigation.

    SciTech Connect

    Odom, C. R.

    2005-01-01

    A student working in a laser laboratory at Los Alamos National Laboratory sustained a serious retinal injury to her left eye when she attempted to view suspended particles in a partially evacuated target chamber. The principle investigator was using the white light from the flash lamp of a Class 4 Nd:YAG laser to illuminate the particles. Since the Q-switch was thought to be disabled at the time of the accident, the principal investigator assumed it would be safe to view the particles without wearing laser eye protection. The Laboratory Director appointed a team to investigate the accident and to report back to him the events and conditions leading up to the accident, equipment malfunctions, safety management causal factors, supervisory and management action/inaction, adequacy of institutional processes and procedures, emergency and notification response, effectiveness of corrective actions and lessons learned from previous similar events, and recommendations for human and institutional safety improvements. The team interviewed personnel, reviewed documents, and characterized systems and conditions in the laser laboratory during an intense six week investigation. The team determined that the direct and primary failures leading to this accident were, respectively, the principle investigator's unsafe work practices and the institution's inadequate monitoring of worker performance. This paper describes the details of the investigation, the human and institutional failures, and the recommendations for improving the laser safety program.

  10. Los Alamos Neutron Science Center

    SciTech Connect

    Kippen, Karen Elizabeth

    2016-11-08

    For more than 30 years the Los Alamos Neutron Science Center (LANSCE) has provided the scientific underpinnings in nuclear physics and material science needed to ensure the safety and surety of the nuclear stockpile into the future. In additio